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Graphene Based Composite Materials - Programmaster.org
Science Conference Proceedings (OSTI)
About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Nanocomposites. Presentation Title, Graphene Based Composite Materials.
XG Sciences, ORNL partner on titanium-graphene composite materials...
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composites. "Graphene is an exciting new material with huge po-tential due to its fast electron mobility, high mechanical strength, and excellent thermal conductivity," said...
XG Sciences, ORNL partner on titaniumgraphene composite materials January 01, 2013 Titaniumgraphene composite specimens prepared for flash thermal diffusivity measurement....
Graphene Reinforced Glass and Ceramic Matrix Composites
About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Ceramic Matrix Composites. Presentation Title, Graphene Reinforced Glass ...
Graphene-based composites as cathode materials for lithium ion batteries
Owing to the superior mechanical, thermal, and electrical properties, graphene was a perfect candidate to improve the performance of lithium ion batteries. Herein, we review the recent advances in graphene-based composites and their application as cathode ...
Libao Chen, Ming Zhang, Weifeng Wei
Graphene Materials in the Flatland
Graphene Materials in the Flatland. Purpose: ... The 2-dimensional material called graphene remained undiscovered until a few years ago. ...
Epitaxial graphene: the material for graphene electronics
The search for an ideal graphene sheet has been a quest driving graphene research. While most research has focused on exfoliated graphene, intrinsic substrate interactions and mechanical disorder have precluded the observation of a number of graphene's expected physical properties in this material. The only graphene candidate that has demonstrated all the essential properties of an ideal sheet is multilayer graphene grown on the SiC(000) surface. Its unique stacking allows nearly all the sheets in the stack to behave like isolated graphene, while the weak graphene-graphene interaction prevents any significant doping or distortion in the band near the Fermi level.
Sprinkle, M.; Soukiassian, P.; de Heer, W.A.; Berger, C.; Conrad, E.H.; (CEA); (GIT)
Session M: Graphene - Materials and Characterization
Jun 24, 2010 ... TMS 2010 Electronic Materials Conference: Session M: Graphene - Materials and Characterization Program Organizers: Mark Goorsky, ...
Nanocomposite of graphene and metal oxide materials
SciTech Connect
Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.
Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo
Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane
DOE Patents (OSTI)
An embodiment of a method of suspending a graphene membrane across a gap in a support structure includes attaching graphene to a substrate. A pre-fabricated support structure having the gap is attached to the graphene. The graphene and the pre-fabricated support structure are then separated from the substrate which leaves the graphene membrane suspended across the gap in the pre-fabricated support structure. An embodiment of a method of depositing material includes placing a support structure having a graphene membrane suspended across a gap under vacuum. A precursor is adsorbed to a surface of the graphene membrane. A portion of the graphene membrane is exposed to a focused electron beam which deposits a material from the precursor onto the graphene membrane. An embodiment of a graphene-based structure includes a support structure having a gap, a graphene membrane suspended across the gap, and a material deposited in a pattern on the graphene membrane.
Zettl, Alexander K.; Meyer, Jannik Christian
Graphene Compositions And Drilling Fluids Derived Therefrom ...
Drilling fluids comprising graphenes and nanoplatelet additives and methods for production thereof are disclosed. Graphene includes graphite oxide, graphene oxide ...
Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties
A green and facile approach was demonstrated to prepare graphene nanosheets/ZnO (GNS/ZnO) composites for supercapacitor materials. Glucose, as a reducing agent, and exfoliated graphite oxide (GO), as precursor, were used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials. The small ZnO particles successfully anchored onto graphene sheets as spacers to keep the neighboring sheets separate. The electrochemical performances of these electrodes were analyzed by cyclic voltammetry, electrochemical impedance spectrometry and chronopotentiometry. Results showed that the GNS/ZnO composites displayed superior capacitive performance with large capacitance (62.2 F/g), excellent cyclic performance, and maximum power density (8.1 kW/kg) as compared with pure graphene electrodes. Our investigation highlight the importance of anchoring of small ZnO particles on graphene sheets for maximum utilization of electrochemically active ZnO and graphene for energy storage application in supercapacitors. - Graphical abstract: Glucose was used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials for supercapacitor. Results showed that the composites have superior capacitive performance. Highlights: > Graphene nanosheets were synthesized via using glucose as a reducing agent. > The reductant and the oxidized product are environmentally friendly. > ZnO grew onto conducting graphene sheets keeping neighboring sheets separate. > The structure improves the contact between the electrode and the electrolyte. > Results showed that these composites have good electrochemical property.
Wang Jun, E-mail: firstname.lastname@example.com [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Gao Zan [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Li Zhanshuang; Wang Bin; Yan Yanxia; Liu Qi [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Mann, Tom [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Zhang Milin [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Jiang Zhaohua [College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)
Composite Materials
Table 8Â Â Â Properties of composites for electrical make-break contacts...272 (d) 31 (c) 39.5 (d) â?¦ â?¦ C,A Wall switches, thermostat controls Silver-nickel 99.7Ag-0.3Ni â?¦ 10.49 â?¦ 100 53 HR15T (c) 79 HR15T (d) â?¦ â?¦ â?¦ â?¦ T â?¦ 95Ag-5Ni PSR 10.41 9.80â??10.41 80â??95 32 HRF (c) 84 HRF (d) 165 (c) 24 (c) â?¦ â?¦ C,A,S Appliance switches 90Ag-10Ni PSR 10.31 9.70â??10.32 75â??90 35 HRF (c) 89 HRF (d)...
Table 2Â Â Â Properties of composites for electrical make-break contacts...HRF (c) 214 (c) 31 (c) â?¦ â?¦ C, A Wall switches, thermostat controls 81 HRF (d) 272 (d) 39.5 (d) â?¦ â?¦ Silver-nickel 99.7Ag-0.3Ni â?¦ 10.49 â?¦ 100 53 HR15T (c) â?¦ â?¦ â?¦ â?¦ T â?¦ 79 HR15T (d) â?¦ â?¦ â?¦ â?¦ 95Ag-5Ni PSR 10.41 9.80â??10.41 80â??95 32 HRF (c) 165 (c) 24 (c) â?¦ â?¦ C, A, S Appliance switches 84 HRF (d) â?¦ â?¦ â?¦ â?¦...
Graphene: from materials science to particle physics
E-Print Network (OSTI)
Since its discovery in 2004, graphene, a two-dimensional hexagonal carbon allotrope, has generated great interest and spurred research activity from materials science to particle physics and vice versa. In particular, graphene has been found to exhibit outstanding electronic and mechanical properties, as well as an unusual low-energy spectrum of Dirac quasiparticles giving rise to a fractional quantum Hall effect when freely suspended and immersed in a magnetic field. One of the most intriguing puzzles of graphene involves the low-temperature conductivity at zero density, a central issue in the design of graphene-based nanoelectronic components. While suspended graphene experiments have shown a trend reminiscent of semiconductors, with rising resistivity at low temperatures, most theories predict a constant or even decreasing resistivity. However, lattice field theory calculations have revealed that suspended graphene is at or near the critical coupling for excitonic gap formation due to strong Coulomb interactions, which suggests a simple and straightforward explanation for the experimental data. In this contribution we review the current status of the field with emphasis on the issue of gap formation, and outline recent progress and future points of contact between condensed matter physics and Lattice QCD.
Joaquín E. Drut; Timo A. Lähde; Eero Tölö
Vorbeck Materials Licenses Graphene-based Battery Technologies ...
Vorbeck Materials Licenses Graphene-based Battery Technologies Vorbeck Materials Corp of Jessup, MD participated in the America's Next Top Energy Innovator program ...
Composite of refractory material
A composite refractory material composition comprises a boron carbide matrix and minor constituents of yttrium-boron-oxygen-carbon phases uniformly distributed throughout the boron carbide matrix.
Holcombe, Cressie E. (Knoxville, TN); Morrow, Marvin S. (Kingston, TN)
Holcombe, C.E.; Morrow, M.S.
Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries
Graphene-modified LiFePO{sub 4} composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO{sub 4} nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO{sub 4} primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO{sub 4} nanoparticles and graphene sheets was beneficial for Li{sup +} diffusion. The composite cathode material could deliver a capacity of 70 mAh g{sup -1} at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.
Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.
Graphene materials having randomly distributed two-dimensional structural defects
Graphene-based storage materials for high-power battery applications are provided. The storage materials are composed of vertical stacks of graphene sheets and have reduced resistance for Li ion transport. This reduced resistance is achieved by incorporating a random distribution of structural defects into the stacked graphene sheets, whereby the structural defects facilitate the diffusion of Li ions into the interior of the storage materials.
Kung, Harold H; Zhao, Xin; Hayner, Cary M; Kung, Mayfair C
Porous graphene-based materials for electrochemical energy storage
In this presentation, I will discuss some methods that have been demonstrated in our lab for preparing high-surface-area graphene electrode materials for ...
Composite Materials Committee
Metal-Matrix Composites in Industry: A Database of Companies, Materials, and Products (TMS Members Only) · Technical Questions @ TMS: Metal-Matrix ...
Graphene-based Materials for Biosensing and Bioimaging
Graphene, a free-standing two-dimensional crystal with one-atom thickness, exhibits distinct properties that are highly attractive for biosensing and bioimaging, such as a high electrical conductivity, a large planar area, and an excellent ability to quench fluorescence. This article selectively reviews recent advances in the field of graphene-based materials for biosensing and bioimaging. In particular, graphene-based enzyme biosensors, DNA biosensors, and immunosensors are summarized in detail. Graphene-based biotechnology for cell imaging is also described. Future perspectives and possible challenges in this rapidly developing area are also discussed.
Du, Dan; Yang, Yuqi; Lin, Yuehe
The Preparation and Property of Few-Layered Graphene/Benzalkonium Chloride Composite
In order to research and development a novel antibacterial material which is used to deal with the drinking water, few-layered grapheme/benzalkonium chloride composite was prepared by introducing different content of quaternary ammonium salt into layered ... Keywords: graphene, benzalkonium chloride, antibacterial, water treatment
A-gui Xie; Xiang Cai; Shao-zao Tan
1 Beyond Graphene - Novel Nanosheets of 2D Crystalline Materials ...
that graphene, a 2D nanosheet form of carbon, can exist as a stable material and exceptional properties that are not observed in 3D or 1D form of carbon are ...
SeZnSb alloy and its nano tubes, graphene composites properties
Composite can alter the individual element physical property, could be useful to define the specific use of the material. Therefore, work demonstrates the synthesis of a new composition Se{sub 96}-Zn{sub 2}-Sb{sub 2} and its composites with 0.05% multi-walled carbon nano tubes and 0.05% bilayer graphene, in the glassy form. The diffused amorphous structure of the multi walled carbon nano tubes and bilayer gaphene in the Se{sub 96}-Zn{sub 2}-Sb{sub 2} alloy have been analyzed by using the Raman, X-ray photoluminescence spectroscopy, Furrier transmission infrared spectra, photoluminescence, UV/visible absorption spectroscopic measurements. The diffused prime Raman bands (G and D) have been appeared for the multi walled carbon nano tubes and graphene composites, while the X-ray photoluminescence core energy levels peak shifts have been observed for the composite materials. Subsequently the photoluminescence property at room temperature and a drastic enhancement (upto 80%) in infrared transmission percentage has been obtained for the bilayer graphene composite, along with optical energy band gaps for these materials have been evaluated 1.37, 1.39 and 1.41 eV.
Singh, Abhay Kumar [Department of Physics, Indian Institute of Physics, Bangalore-560012 (India)
Graphene: Amazing Material Found Thanks to Scotch Tape and Persistent
Office of Science (SC) Website
1 » Graphene: 1 » Graphene: Amazing Material Found Thanks to Scotch Tape and Persistent Science News Featured Articles 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 Science Headlines Presentations & Testimony News Archives Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 03.25.11 Graphene: Amazing Material Found Thanks to Scotch Tape and Persistent Science What do you get when you combine pencil lead, scotch tape, and persistent science? A Nobel Prize . . . and a new world of potential applications. Print Text Size: A A A Subscribe FeedbackShare Page That's the developing story of graphene, an amazing material that can be found in pencil lead. Pencil "lead" is actually a mixture of clay and the
Nanostructured composite reinforced material
A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.
Seals, Roland D. (Oak Ridge, TN); Ripley, Edward B. (Knoxville, TN); Ludtka, Gerard M. (Oak Ridge, TN)
Simple synthesis and enhanced performance of graphene oxide-gold composites
Graphene oxide-gold composites were prepared by one-step reaction in aqueous solution, where the gold nanoparticles were deposited on the graphene oxide during their synthesis process. Transmission electron morphology, X-ray diffraction, Roman spectra, ...
Min Song; Lulu Yu; Yimin Wu
Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density
supercapacitors of high energy density Qian Cheng a,b , Jie Tang a,b,**, Norio Shinya b , Lu-Chang Qin c as supercapacitor electrodes. Energy density of 188 Wh kgĂ?1 has been obtained. Graphene composite with carbon April 2013 Keywords: Supercapacitor Graphene Carbon nanotube PANI a b s t r a c t Graphene and single
Qin, Lu-Chang
Fabrication, Mechanical Properties, and Biocompatibility of Graphene-Reinforced Chitosan Composites
cleavage of highly ordered pyrolytic graphite (HOPG), graphene has become one of the most fascinating and high elasticity.16-19 Polymer composites containing graphene possess good electric conductivity microscope (TEM, Hitachi H-9000NAR) with an accelerating voltage of 100 kV. The Raman spectra of graphene
Ge, Zigang
Graphene-Based and Graphene-Derived Materials for ...
About this Abstract. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium , Nanostructured Materials for Lithium Ion Batteries and for Supercapacitors.
Hybrid and Hierarchical Composite Materials
Chang Soo Kim, University of Wisconsin -Milwaukee. Scope, Hybrid and hierarchical composite materials have several advantageous characteristics that ...
Graphene bimetallic-like cantilevers: probing graphene/substrate interactions
The remarkable mechanical properties of graphene the thinnest, lightest, and strongest material in existence are desirable in applications ranging from composite materials to sensors and actuators. Here, we demonstrate that these mechanical properties are strongly affected by the interaction with the substrate onto which graphene is deposited. By measuring the temperature-dependent deflection of graphene/substrate bimetallic cantilevers we determine strain, thermal expansion coefficient, and the adhesion force acting on graphene films attached to a substrate. Graphene deposited on silicon nitride (SiNx) is under much larger strain, g 1.5 10 2, compared to graphene on gold (Au), g < 10 3. The thermal expansion coefficient g of graphene attached to SiNx is found to be negative, in the range from ( 5 . . . 1) 10 6K 1 and smaller in magnitude than g of suspended graphene. We also estimate the interfacial shear strength of the graphene/SiNx interface to be 1 GPa at room temperature.
Conley, Hiram J [ORNL; Lavrik, Nickolay V [ORNL; Prasai, Dhiraj [Vanderbilt University; Bolotin, Kirill I [ORNL
Composite materials for electromagnetic shielding
The paper shows up the research results on processing and characterization of composite materials with polymeric matrix (silicone rubber). The materials obtained in laboratory contain metallized nettling like reinforcement material and powdery graphite ... Keywords: attenuation, filling additions, frequency, plated nettling, polymeric composite on de basis of silicone rubber, shielding effectiveness
Stoian Elena Valentina; Rizescu Cristiana; Iordache Iulian; Ionita Gheorghe; Bacinschi Zorica
Epitaxial Graphene: Designing a New Electronic Material
About this Abstract. Meeting, 2010 Electronic Materials Conference. Symposium, TMS 2010 Electronic Materials Conference. Presentation Title, Epitaxial ...
Graphene-based Materials - Programmaster.org
About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Mechanical Behavior of Low Dimensional Materials. Presentation Title ...
Graphene-based materials in electrodes and separators in ...
In our laboratory, we have explored the use of graphene and graphene oxide for applications in electrodes and separators. A 3-D network of electrically ...
Synthesis and applications of materials and polymers containing graphenic and/or triptycene moities
In this thesis, molecular design is used to synthesize novel materials with specific properties. The materials presented herein are based on two motifs. In part I, new methods of functionalizing graphenic materials and the ...
Sydlik, Stefanie A. (Stefanie Arlene)
Materials - Recycling - Polymer Matrix Composites
Recycling of Polymer Matrix Composites Recycling of Polymer Matrix Composites Polymer matrix composites Carbon fibers recovered from a epoxy-based polymer matrix composite. Carbon fiber reinforced polymer matrix composites (PMCs) are materials with superior strength-to-weight ratios. Finding increased applications in the aerospace industry, PMCs are now being evaluated for possible use in automobile construction. The materialÂ's high cost, however, along with concerns about whether the PMCs will be recyclable when the vehicles reach the end of their useful lives, are barriers to its widespread use. With funding provided by the U.S. Department of EnergyÂ's Vehicle Technologies Program (formerly called the Office of Advanced Transportation Technologies), Argonne is developing an efficient and cost-effective
Self assembled multi-layer nanocomposite of graphene and metal oxide materials
Nanocomposite materials having at least two layers, each layer consisting of one metal oxide bonded to at least one graphene layer were developed. The nanocomposite materials will typically have many alternating layers of metal oxides and graphene layers, bonded in a sandwich type construction and will be incorporated into an electrochemical or energy storage device.
Liu, Jun; Aksay, Ilhan A; Choi, Daiwon; Kou, Rong; Nie, Zimin; Wang, Donghai; Yang, Zhenguo
Graphene Coated with Titanium Nitride as Electrode Materials for ...
About this Abstract. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium , 2013 and Beyond: Flexible Electronics. Presentation Title, Graphene Coated ...
Graphene-Based Nano-Composites for Electrochemical Energy ...
In this talk, recent advances in controlled synthesis of graphene-based nanocomposites as advanced electrodes for supercapacitor and lithium ion battery will ...
Defect Structures and Electronic Properties of Graphene
Defect Structures and Electronic Properties of Graphene. Summary: Graphene and related materials have remarkable physical ...
Enhanced Heat Transfer in Composite Materials.
??Many composite materials are composed of a matrix reinforced with fibers. Carbon fiber composites are currently being used for high heat transfer applications. Carbon fibers… (more)
Pathak, Sayali V.
An analytic formula is derived for the elastic bending modulus of monolayer graphene based on an empirical potential for solid-state carbon atoms. Two physical origins are identified for the non-vanishing bending stiffness of the atomically thin graphene sheet, one due to the bond-angle effect and the other resulting from the bond-order term associated with the dihedral angles. The analytical prediction compares closely with ab initio energy calculations. Pure bending of graphene monolayers into cylindrical tubes is simulated by a molecular mechanics approach, showing slight nonlinearity and anisotropy in the tangent bending modulus as the bending curvature increases. An intrinsic coupling between bending and in-plane strain is noted for graphene monolayers rolled into carbon nanotubes. (Some figures in this article are in colour only in the electronic version) The unique two-dimensional (2D) lattice structure and physical properties of graphene have attracted tremendous interest recently. In particular, rippling of suspended graphene monolayers has been observed, with mesoscopic amplitude
Qiang Lu; Marino Arroyo; Rui Huang
A 3D Porous Architecture of Si/graphene Nanocomposite as High-performance Anode Materials for Li-ion Batteries
A 3D porous architecture of Si/graphene nanocomposite has been rationally designed and constructed through a series of controlled chemical processes. In contrast to random mixture of Si nanoparticles and graphene nanosheets, the porous nanoarchitectured composite has superior electrochemical stability because the Si nanoparticles are firmly riveted on the graphene nanosheets through a thin SiO{sub x} layer. The 3D graphene network enhances electrical conductivity, and improves rate performance, demonstrating a superior rate capability over the 2D nanostructure. This 3D porous architecture can deliver a reversible capacity of {approx}900 mA h g{sup -1} with very little fading when the charge rates change from 100 mA g{sup -1} to 1 A g{sup -1}. Furthermore, the 3D nanoarchitechture of Si/graphene can be cycled at extremely high Li{sup +} extraction rates, such as 5 A g{sup -1} and 10 A g{sup -1}, for over than 100 times. Both the highly conductive graphene network and porous architecture are considered to contribute to the remarkable rate capability and cycling stability, thereby pointing to a new synthesis route to improving the electrochemical performances of the Si-based anode materials for advanced Li-ion batteries.
Xin X.; Zhu Y.; Zhou, X.; Wang, F.; Yao, X.; Xu, X.; Liu, Z.
Nanocomposite materials of alternately stacked C60 monolayer and graphene
We synthesized the novel nanocomposite consisting alternately of a stacked single graphene sheet and a C60 monolayer by using the graphite intercalation technique in which alkylamine molecules help intercalate large C60 molecules ...
Makoto Ishikawa; Shu Kamiya; Shoji Yoshimoto; Masaru Suzuki; Daisuke Kuwahara; Naruo Sasaki; Kouji Miura
Mechanics of Interfacial Composite Materials
Recent experiments and simulations have demonstrated that particle-covered interfaces can exist in stable non-spherical shapes as a result of the steric jamming of the interfacially trapped particles, which confers the interface with solid-like properties. We provide an experimental and theoretical characterization of the mechanical properties of these armored objects, with attention given to the two-dimensional granular state of the interface. Small inhomogeneous stresses produce a plastic response while homogeneous stresses produce a weak elastic response. Shear-driven particle-scale rearrangements explain the basic threshold needed to obtain the near-perfect plastic deformation that is observed. Furthermore, the inhomogeneous stress state of the interface is exhibited experimentally by using surfactants to destabilize the particles on the surface. Since the interfacially trapped particles retain their individual characteristics, armored interfaces can be recognized as a kind of composite material with distinct chemical, structural and mechanical properties.
Anand Bala Subramaniam; Manouk Abkarian; L. Mahadevan; Howard A. Stone
Enhancing Graphene-derived Materials through Multimodal and Self-healable Interfaces
Recent studies have shown that graphene-derived materials not only feature outstandingly multifunctional properties, but also act as model materials to implant nanoscale structural engineering insights into their macroscopic performance optimization. Functionalizing the interfaces between graphene sheets by interlayer crosslinks has been proven to be an effective route to tune the mechanical properties. Here we explore the graphene-derived material with a layer-by-layer structure and multiple crosslinking mechanisms. The effects of multimodal and self-healable crosslinks are assessed in terms of interlayer loading transfer capability. The results show that the brick-and-motar hierarchy and synergetic effects from different crosslinks enable synergetic enhancement in the strength and toughness. The findings here could shed light on the development of high-performance paper-, fiber- or film-like macroscopic materials from monolayer nanosheets with nanoengineerable interfaces.
Yilun Liu; Zhiping Xu
Polyolefin composites containing a phase change material
A composite useful in thermal energy storage, said composite being formed of a polyolefin matrix having a phase change material such as a crystalline alkyl hydrocarbon incorporated therein, said polyolefin being thermally form stable; the composite is useful in forming pellets, sheets or fibers having thermal energy storage characteristics; methods for forming the composite are also disclosed.
Salyer, Ival O. (Dayton, OH)
Symposium K: Composites and Hybrid Materials
Aug 3, 2010 ... The Tc was determined by electrical resistivity and magnetization to be ... The introduction of composite materials are welcomed in the market ...
Process for producing dispersed particulate composite materials
This invention is directed to a process for forming noninterwoven dispersed particulate composite products. In one case a composite multi-layer film product comprises a substantially noninterwoven multi-layer film having a plurality of discrete layers. This noninterwoven film comprises at least one discrete layer of a first material and at least one discrete layer of a second material. In another case the first and second materials are blended together with each other. In either case, the first material comprises a metalloid and the second material a metal compound. At least one component of a first material in one discrete layer undergoes a solid state displacement reaction with at least one component of a second material thereby producing the requisite noninterwoven composite film product. Preferably, the first material comprises silicon, the second material comprises Mo.sub.2 C, the third material comprises SiC and the fourth material comprises MoSi.sub.2.
Henager, Jr., Charles H. (Richland, WA); Hirth, John P. (Viola, ID)
Composite Materials Symposium: Session IV
Jul 29, 2010 ... Owing to its unique characteristics – like morphology and chemical composition-, fly ash has been identified as a potential reinforcing phase for ...
F. Composites and Hybrid Materials
Low-velocity Impact Response of Sandwich Composites with FRP Facesheets and Nanoclay-wood Flour Modified Polyurethane Foam · Manufacturing Process
Thermal treatment effects on charge storage performance of graphene-based materials for supercapacitors
Graphene materials were synthesized by reduction of exfoliated graphene oxide sheets by hydrazine hydrate and then thermally treated in nitrogen to improve the surface area and their electrochemical performance as electrical double-layer capacitor electrodes. The structural and surface properties of the prepared reduced graphite oxide (RGO) were investigated using atomic force microscopy, scanning electron microscopy, Raman spectra, X-ray diffraction, and nitrogen adsorption / desorption. RGO forms a continuous network of crumpled sheets, which consist of numerous few-layer and single-layer graphenes. Electrochemical studies were conducted by cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge measurements. The modified RGO materials showed enhanced electrochemical performance, with maximum specific capacitance of 96 F/g, energy density of 12.8 Wh/kg, and power density of 160 kW/kg. The results demonstrate that thermal treatment of RGO at selected conditions is a convenient and efficient method for improving specific capacitance, energy, and power density.
Zhang, Hongxin [ORNL; Bhat, Vinay V [ORNL; Gallego, Nidia C [ORNL; Contescu, Cristian I [ORNL
Composite, nanostructured, super-hydrophobic material
A hydrophobic disordered composite material having a protrusive surface feature includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a protrusive surface feature, the protrusive feature being hydrophobic.
D' Urso, Brian R. (Clinton, TN); Simpson, John T. (Clinton, TN)
Composite materials and method of making
A method for forming improved composite materials using a thermosetting polyester urethane hybrid resin, a closed cavity mold having an internal heat transfer mechanism used in this method, and the composite materials formed by this method having a hybrid of a carbon fiber layer and a fiberglass layer.
Simmons, Kevin L [Kennewick, WA; Wood, Geoffrey M [North Saanich, CA
Defective graphene as promising anode material for Na-ion battery and Ca-ion battery
We have investigated adsorption of Na and Ca on graphene with divacancy (DV) and Stone-Wales (SW) defect. Our results show that adsorption is not possible on pristine graphene. However, their adsorption on defective sheet is energetically favorable. The enhanced adsorption can be attributed to the increased charge transfer between adatoms and underlying defective sheet. With the increase in defect density until certain possible limit, maximum percentage of adsorption also increases giving higher battery capacity. For maximum possible DV defect, we can achieve maximum capacity of 1459 mAh/g for Na-ion batteries (NIBs) and 2900 mAh/g for Ca-ion batteries (CIBs). For graphene full of SW defect, we find the maximum capacity of NIBs and CIBs is around 1071 mAh/g and 2142 mAh/g respectively. Our results will help create better anode materials with much higher capacity and better cycling performance for NIBs and CIBs.
Datta, Dibakar; Shenoy, Vivek B
Polymer/Elastomer and Composite Material Science
/ Elastomer and / Elastomer and Composite Material Science KEVIN L. SIMMONS Pacific Northwest National Laboratory, Richland, WA DOE Headquarters, Forrestal Bldg. October 17-18, 2012 January 17, 2013 email@example.com 1 Outline Hydrogen production, transmission, distribution, delivery system Common themes in the hydrogen system Automotive vs infrastructure Hydrogen use conditions Polymer/elastomer and composites compatibility? Common materials in BOP components, hoses, and liners Common materials in composite tank and piping Material issues Polymers/Elastomers Composites Questions 2 Main Points to Remember 1) Polymers are extensively used in hydrogen and fuel cell applications 2) Hydrogen impact on polymers is not well understood 3) Next steps 3 4 Hydrogen Production Systems
Mechanics Methodology for Textile Preform Composite Materials
NASA and its contractors have completed a program to develop a basic mechanics underpinning for textile composites. Three major deliverables were produced by the program: (1.) a set of test methods for measuring material properties and design allowables, ...
Jr Clarence C. Poe
Combustion joining of refractory materials: Carboncarbon composites
Combustion joining of refractory materials: CarbonÂcarbon composites Jeremiah D.E. White DepartmentÂcarbon composite is achieved by employing self-sustained, oxygen-free, high-temperature combustion reactions to a used "core" to produce a brake that meets the performance specifications. The combustion-joining (CJ
Mukasyan, Alexander
Method of making a composite refractory material
A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000.degree. C. to form a composite refractory material.
Morrow, Marvin S. (Kingston, TN); Holcombe, Cressie E. (Knoxville, TN)
CC6, Graphene Reinforced Composites as Efficient Thermal ...
Efficient thermal management of electronics, optoelectronics and photonic devices require better thermal interface materials (TIMs). Current TIMs are based on ...
Graphene and its Hybrid Nanostructures for Nanoelectronics and Energy Applications
modification of graphene. Advanced Materials, 2008. 20 (16):S. Novoselov. The rise of graphene. Nature Materials, 2007.transport in suspended graphene. Nature Nanotechnology,
Sulfur-graphene oxide material for lithium-sulfur battery cathodes
Sulfur-graphene oxide material for lithium-sulfur battery cathodes Sulfur-graphene oxide material for lithium-sulfur battery cathodes Theoretical specific energy and theoretical energy density Scanning electron micrograph of the GO-S nanocomposite June 2013 Searching for a safer, less expensive alternative to today's lithium-ion batteries, scientists have turned to lithium-sulfur as a possible chemistry for next-generation batteries. Li/S batteries have several times the energy storage capacity of the best currently available rechargeable Li-ion battery, and sulfur is inexpensive and nontoxic. Current batteries using this chemistry, however, suffer from extremely short cycle life-they don't last through many charge-discharge cycles before they fail. A research team led by Elton Cairns and Yuegang Zhang has developed a new
The present invention provides a composite material suitable for use in an anode for a lithium ion battery, the composite material comprising a layer of a lithium ...
Shanghai Yuke Composite Material Co Ltd | Open Energy Information
Open Energy Info (EERE)
China Zip 20012 Sector Wind energy Product Composite material maker for wind power generation References Shanghai Yuke Composite Material Co., Ltd1 LinkedIn...
Modeling of Physical Properties of Composite Materials
Recent progress in three different areas involving the modeling of the physical properties of composites is reviewed. These include: (i) theoretical approaches to microstructure/property relations; (ii) X-ray microtomography, an imaging technique that enables one to obtain high-resolution three-dimensional microstructural phase information of a composite sample in a non-intrusive manner; and (ii) topology optimization, a promising numerical technique that enables one to design composites with tailored material properties. Current limitations and future research needs are described.
S. Torquato
Novel Composite Materials Demonstrate Ultra-sensitivity
2, Issue 25 2, Issue 25 Novel Composite Materials Demonstrate Ultra-sensitivity Gold nanowires on graphite templates used in gas sensing application page 2 Coronary Stent Wins Technology Transfer Award page 4 University of Oregon Team Wins Competition for Commercializing NETL Technology page 5 the ENERGY lab NATIONAL ENERGY TECHNOLOGY LABORATORY 2 Novel Composite Materials Demonstrate Ultra-sensitivity-Gold nanowires on graphite templates used in gas sensing applications ____________________2 Coronary Stent Wins Technology Transfer Award ________4 University of Oregon Team Wins Competition for Commercializing NETL Technology __________________5 NETL & WVU Researchers Design New Catalysts for CO 2 Management ___________________________________6 Structurally Dynamic MOF Sorbent Selectively Adsorbs
Graphene-like 2D-layered Materials for Nanoelectronics & Sensing ...
Abstract Scope, Recently, layered 2D crystals similar to graphene have been ... the best graphene transistors at room temperature, with comparable mobilities.
Test Plan for Composite Hydrogen Getter Materials
The intent of this test plan is to provide details of the Savannah River Technology Center (SRTC) effort to evaluate composite getter materials for eventual use in expanding the wattage limits for transportation of contact-handled transuranic waste (CH-TRU). This effort is funded by the Mixed Waste Focus Area (MWFA) under Technical Task Plan (TTP) SR-1-9-MW-45 and is the result of a competitive process initiated by a MWFA request for proposals. In response to this request, SRTC presented data on several composite getter materials that demonstrated good potential for application in transportation of transuranic wastes. The tests outlined in the SRTC proposal for composite getter materials should demonstrate compliance with functional requirements provided by the MWFA in a Statement of Work (SOW) which accompanied the request for proposals. Completion of Phase 1 testing, as defined in the TTP, should provide sufficient data to determine if composite getters should progress to Phase s 2 and 3. These test results will provide support for future safety reviews as part of the Transuranic Package Transporter-II (TRUPACT-II) certification process to utilize getter technology. This test plan provides details of the test descriptions, test objectives, required measurements, data quality objectives, data analysis, and schedule information relevant to Phase 1 of the TTP. The results of these tests are expected to help identify any potential weaknesses in the use of composite getter for transportation of CH-TRU wastes. Where a potential weakness is identified, this will be addressed as part of Phase 2 of the proposed effort. It is also important to recognize that these tests are focused on the individual composite getter materials and not the engineered system that would eventually be used in a TRUPACT-II. However, these test results will be very helpful in establishing the requirements for the design of a TRUPACT-II getter system that is included as part of the propo sed Phase 3 effort.
Livingston, R.R.
Machine augmented composite materials for damping purposes
In this study the energy dissipation performance of machine augmented composite (MAC) materials is investigated. MAC materials are formed by inserting simple machines into a matrix material. In this work the machines take the form of fluid filled tubes, and the tube cross-sectional geometry induces fluid flow when it is deformed in its plane. This flow dissipates mechanical energy, and thus provides the composite material with attractive damping properties. The objective of this study is to gain insight into the geometry, the material property combinations, and the boundary conditions that are effective in producing high damping MAC materials. Particular attention is given to tube geometry and to dimensionless parameters that govern the energy dissipation efficiency of a MAC lamina. An important dimensionless parameter is the ratio of solid elastic moduli to the product of the driving frequency and the fluid dynamic viscosity. This is a measure of the ratio of elastic forces in the solid material to the viscous forces in the fluid material that makes up a MAC lamina. Governing equations and simulation methods are discussed. Simplified equations are derived to predict the pressure generated when a tube/matrix cell is squeezed with zero pressure end conditions. Transient, three dimensional finite element models are also used to predict the performance of the damping MAC materials with zero pressure at the ends of the tubes. For the geometry and material properties considered, the highest energy dissipation efficiency predicted by these models is approximately 0.8 out of a maximum of 1.0.
McCutcheon, David Matthew
Alkali metal protective garment and composite material
A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.
Ballif, III, John L. (Salt Lake City, UT); Yuan, Wei W. (Seattle, WA)
Multifunctionality and control of the crumpling and unfolding of large-area graphene
Crumpled graphene films are widely used, for instance in electronics1, energy storage2,3, composites4,5 and biomedicine6. Although it is known that the degree of crumpling affects graphene's properties and the performance of graphene-based devices and materials3,5,7, the controlled folding and unfolding of crumpled graphene films has not been demonstrated. Here we report an approach to reversibly control the crumpling and unfolding of large-area graphene sheets. We show with experiments, atomistic simulations and theory that, by harnessing the mechanical instabilities of graphene adhered on a biaxially pre-stretched polymer substrate and by controlling the relaxation of the pre-strains in a particular order, graphene films can be crumpled into tailored self-organized hierarchical structures that mimic superhydrophobic leaves. The approach enables us to fabricate large-area conductive coatings and electrodes
Jianfeng Zang; Seunghwa Ryu; Nicola Pugno; Qiming Wang; Qing Tu; Markus J. Buehler; Xuanhe Zhao
First Observation of Plasmarons in Graphene
First Observation of Plasmarons First Observation of Plasmarons in Graphene First Observation of Plasmarons in Graphene Print Wednesday, 30 June 2010 00:00 An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has been found, this work is the first observation of their distinct energy bands in graphene, or indeed in any material. The discovery may hasten the day when graphene can be used for "plasmonics" to build ultrafast computers-perhaps even room-temperature quantum computers-plus a wide range of other tools and applications.
First Observation of Plasmarons in Graphene Print First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1 have found that composite particles called plasmarons play a vital role in determining graphene's properties. A plasmaron consists of a charge carrier (electron or hole) coupled with a plasmon-an electron density wave. Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has been found, this work is the first observation of their distinct energy bands in graphene, or indeed in any material. The discovery may hasten the day when graphene can be used for "plasmonics" to build ultrafast computers-perhaps even room-temperature quantum computers-plus a wide range of other tools and applications.
Composite materials for thermal energy storage
The present invention discloses composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These phase change materials do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions, such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.
Benson, David K. (Golden, CO); Burrows, Richard W. (Conifer, CO); Shinton, Yvonne D. (Northglenn, CO)
A composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These PCM's do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon, siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.
Benson, D.K.; Burrows, R.W.; Shinton, Y.D.
Fatigue Characterisitcs of CNT Reinforced Al Composite Materials ...
A-59: The Use of Conductive Carbon Nanotubes/Polymer Nonwoven Nanofiber Composites as Shielding Materials for Electromagnetic Interference and ...
Filler Materials for Polyphenylenesulphide Composite Coatings: Preprint
DOE Green Energy (OSTI)
Researchers at Brookhaven National Laboratory and the National Renewable Energy Laboratory have tested polymer-based coating systems to reduce the capital equipment and maintenance costs of heat exchangers in corrosive and fouling geothermal environments. These coating systems act as barriers to corrosion to protect low-cost carbon steel tubing; they are formulated to resist wear from hydroblasting and to have high thermal conductivity. Recently, new filler materials have been developed for coating systems that use polyphenylenesulphide as a matrix. These materials include boehmite crystals (orthorhombic aluminum hydroxide, which is grown in situ as a product of reaction with the geothermal fluid), which enhance wear and corrosion resistance, and carbon fibers, which improve mechanical, thermal, and corrosion-resistance properties of the composite.
Sugama, T.; Gawlik, K.
Polymer and Composite Materials Meeting Agenda
(all times in Eastern Time Zone) (all times in Eastern Time Zone) Start End Activity POC 08:00 08:45 Reception and badging DOE 08:45 09:00 Welcome and meeting objectives / expectations / time horizon for research activities (targets) Erika Sutherland, Sunita Satyapal 09:00 10:00 Polymer/elastomer and composite material science: key issues, knowledge gaps, R&D/testing data needs (40 min speaking, 20 min Q&A) Kevin Simmons 10:00 10:30 Codes and standards requirements - SAE J2579, SAE J2601: knowledge gaps, R&D data/testing needs Mike Veenstra 10:30 11:00 Break 11:00 11:30 Codes and standards requirements -CSA HGV 4, ASME X and B31: knowledge gaps, R&D data/testing needs Aaron Harris 11:30 12:00 Polymer/elastomer Draft R&D Work Plan ideas / Describe
Method of preparing corrosion resistant composite materials
Method of manufacture of ceramic materials which require stability in severely-corrosive environment having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These surfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.
Kaun, Thomas D. (320 Willow St., New Lenox, IL 60451)
Polymer–Graphene Nanocomposites as Ultrafast-Charge and -Discharge Cathodes for Rechargeable Lithium Batteries
Electroactive polymers are a new generation of 'green' cathode materials for rechargeable lithium batteries. We have developed nanocomposites combining graphene with two promising polymer cathode materials, poly(anthraquinonyl sulfide) and polyimide, to improve their high-rate performance. The polymer-graphene nanocomposites were synthesized through a simple in-situ polymerization in the presence of graphene sheets. The highly dispersed graphene sheets in the nanocomposite drastically enhanced the electronic conductivity and allowed the electrochemical activity of the polymer cathode to be efficiently utilized. This allows for ultrafast charging and discharging - the composite can deliver more than 100 mAh/g within just a few seconds.
Song, Zhiping; Xu, Terrence (Tianren); Gordin, Mikhail; Jiang, Yingbing; Bae, In-Tae; Xiao, Qiangfeng; Zhan, Hui; Liu, Jun; Wang, Donghai
Synthesis of graphene nanosheets via oxalic acid-induced chemical reduction of exfoliated graphite oxide
Preparing high-quality graphene through reduction of graphene oxide (GO) by oxalic acid is demonstrated in this paper. Transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction and Raman spectrometry were taken to confirm the reduction of GO and the formation of graphene under these mild conditions. Thermogravimetric analysis and conductivity measurements further testify the excellent thermal stability and conductivity of the obtained graphene. A possible mechanism for the reduction process was also proposed. Furthermore, a Pt-graphene composite was fabricated on a glassy carbon electrode and excellent electrocatalytic activity towards methanol oxidation was observed. With advantages of low toxicity, simple purification process and high quality of the product, oxalic acid provides a feasible route to prepare graphene from GO under mild conditions, thus facilitating the use of graphene-based materials for large-scale applications.
Song, Peng; Zhang, Xiao-Yan; Sun, Mingxun; Cui, Xiao-Li; Lin, Yuehe
Method for preparing polyolefin composites containing a phase change material
A composite useful in thermal energy storage, said composite being formed of a polyolefin matrix having a phase change material such as a crystalline alkyl hydrocarbon incorporated therein. The composite is useful in forming pellets, sheets or fibers having thermal energy storage characteristics; methods for forming the composite are also disclosed.
Biocompatible Graphene Coatings for Biological Applications
About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Next Generation Biomaterials. Presentation Title, Biocompatible Graphene ...
A Roadmap for Engineering Piezoelectricity in Graphene
Roadmap for Engineering Piezoelectricity in Graphene A Roadmap for Engineering Piezoelectricity in Graphene Doping this 'Miracle Material' May Lead to New Array of Nanoscale...
Graphene-based Material Systems for Nanoelectronics and Energy Storage Devices
Graphene Oxide" Angewandte Chemie-International EditionDevices" Angewandte Chemie- International Edition 2010, 49,Devices" Angewandte Chemie- International Edition 2010, 49,
Guo, Shirui
Research and Development of Nano-Composite Materials for ...
Presentation Title, Research and Development of Nano-Composite Materials for Hydrogen Storage. Author(s), Yoshitsugu Kojima. On-Site Speaker (Planned) ...
bylaws of the composite materials committee of the minerals, metals ...
Emerging and developing technologies that possess fundamental features or characteristics of composite materials are also considered within the scope of the ...
Coherent electron transport through freestanding graphene junctions with metal contacts: a materials approach
In this article we highlight recent work in which we computed the spin unpolarized coherent electron transport through two terminal nanoscale graphene/metal junctions using equilibrium Green's functions coupled to Density functional theory, capturing ... Keywords: First-principles quantum transport, Graphene/metal junctions, Tight-binding method
Salvador Barraza-Lopez
Fibrous Materials, Polymer and Ceramic Matrix Composites
Aug 9, 2013 ... To meet with the demand of aerospace technology for high performance ... This composite showed the higher yield and maximum compressive ...
Innovative and Nano-composite Materials
Mar 4, 2013 ... The new disintegrable composites have been used in multiple-zone hydraulic fracturing tools and other oilfield applications, and have proven ...
Composite materials with integrated embedded sensing networks
43 3.2.1 Specimen layup and69 4.2.1 Specimen layup andComposite laminate prepreg layup sequences for creating [0
Schaaf, Kristin Leigh
Green Composite Materials: Development, Manufacturing and Testing
Scope, The intent of this symposium is to highlight new advances and research in the area of bio-based composites including those derived from both wood and ...
Advances in Composite, Cellular and Natural Materials
Compressive Properties of Closed-Cell Aluminum Foams Reinforced with Fly Ash ... Composites Fabricated by Mechanical Alloying and Vacuum Hot Pressing.
Preparation of Ag{sub 2}S-Graphene nanocomposite from a single source precursor and its surface-enhanced Raman scattering and photoluminescent activity
Ag{sub 2}S-Graphene nanocomposite was prepared via a relatively facile hydrothermal method, using a single-source molecular (silver diethyldithiocarbamate [Ag(DDTC)]) as precursor and graphene sheets as a support material. The composite was characterized by X-ray power diffraction, X-ray photoelectron spectroscopy, Field-emission scanning electron microscope, transmission electron microscopy, Fourier transform infrared, Raman spectra and fluorescence spectroscopy. The experimental results show that the Ag{sub 2}S-Graphene nanocomposite displays surface-enhanced Raman scattering (SERS) activity for graphene oxide and reveals relatively better fluorescence property compared with pure Ag{sub 2}S. Highlights: {yields} Ag{sub 2}S nanoparticles are deposited on graphene sheets via a single source precursor. {yields} Graphene oxide is reduced to graphene in the hydrothermal reaction process. {yields} Ag{sub 2}S-Graphene system displays surface-enhanced Raman scattering activity and relatively better fluorescence property.
Pan Shugang; Liu Xiaoheng, E-mail: email@example.com; Wang Xin
T. Fang, W. W. Xu,"Supercapacitor performances of thermallyHigh Energy Density Supercapacitor Based on a Hybrid CarbonChen, Y. S. Chen,"Supercapacitor Devices Based on Graphene
H. Weller,"Carbon Supported CdSe Nanocrystals" Journal ofVersatile Formation of CdSe Nanoparticle-Single WalledV. Kamat,"Fortification of CdSe Quantum Dots with Graphene
Light Weight Materials - Composites and Nanocomposites
Oct 18, 2010 ... To save material only the fracturing interface was reinforced with the carbon nanotube mat. Different functionalization's of the CNT were used to ...
Composition And Method For Removing Photoresist Materials From Electronic
Composition And Method For Removing Photoresist Materials From Composition And Method For Removing Photoresist Materials From Electronic Components Composition And Method For Removing Photoresist Materials From Electronic Components The invention is a combination of at least one dense phase fluid and at least one dense phase fluid modifier. Available for thumbnail of Feynman Center (505) 665-9090 Email Composition And Method For Removing Photoresist Materials From Electronic Components The invention is a combination of at least one dense phase fluid and at least one dense phase fluid modifier which can be used to contact substrates for electronic parts such as semiconductor wafers or chips to remove photoresist materials which are applied to the substrates during manufacture of the electronic parts. The dense phase fluid modifier is one
Multiscale Modeling and Homogenization of Composite Materials
where for ? = 52 we have carbon-fiber material properties.52, which gives us a carbon fiber. Figure 7.18: Fibers with52, which gives us a carbon fiber. To conduct the multiscale
Mseis, George
Upward Flame Spread on Composite Materials
... Since these materials are the result of a hand lay-up process, there could also be local variations in the amount of resin present in a given ply layer. ...
Digital cellular solids : reconfigurable composite materials
Digital materials are comprised of a small number of types of discrete physical building blocks, which assemble to form constructions that meet the versatility and scalability of digital computation and communication ...
Cheung, Kenneth Chun-Wai
Metal oxide composite dosimeter method and material
The present invention is a method of measuring a radiation dose wherein a radiation responsive material consisting essentially of metal oxide is first exposed to ionizing radiation. The metal oxide is then stimulating with light thereby causing the radiation responsive material to photoluminesce. Photons emitted from the metal oxide as a result of photoluminescence may be counted to provide a measure of the ionizing radiation.
Miller, Steven D. (Richland, WA)
What is graphene?
Graphene is a 2D material with a honeycomb lattice structure made of sp2 bonded carbon atoms. Graphene is essentially the mother of all graphitic materials - it can be formed into buckyballs and nanotubes, etched into nanoribbons, or stacked into bulk ...
Raghunath Murali; James D. Meindl
Aluminum - Fly Ash Metal Matrix Composites as Advanced Automobile Material
Metal matrix composites such as silicon carbide-aluminum, alumina-aluminum, and graphite-aluminum represent a class of emerging materials with significant potential for commercial use in the auto and aerospace industries. In industrial foundry trials, a joint industry and Department of Energy project demonstrated a promising new process for producing a low cost aluminum metal matrix composite containing fly ash particles.
Bilayer Graphene Gets a Bandgap
Bilayer Graphene Gets a Bandgap Bilayer Graphene Gets a Bandgap Bilayer Graphene Gets a Bandgap Print Wednesday, 26 August 2009 00:00 Graphene is the two-dimensional crystalline form of carbon whose extraordinary electron mobility and other unique features hold great promise for nanoscale electronics and photonics. But without a bandgap, graphene's promise can't be realized. As with monolayer graphene, bilayer graphene also has a zero bandgap and thus behaves like a metal. But a bandgap can be introduced if an electric displacement field is applied to the two layers; the material then behaves like a semiconductor. A team of researchers from Berkeley has engineered a bandgap in bilayer graphene that can be precisely controlled from 0 to 250 meV. With precision control of its bandgap over a wide range, plus independent manipulation of its electronic states through electrical doping, dual-gated bilayer graphene becomes a remarkably flexible tool for nanoscale electronic devices.
Enabling graphene nanoelectronics.
Recent work has shown that graphene, a 2D electronic material amenable to the planar semiconductor fabrication processing, possesses tunable electronic material properties potentially far superior to metals and other standard semiconductors. Despite its phenomenal electronic properties, focused research is still required to develop techniques for depositing and synthesizing graphene over large areas, thereby enabling the reproducible mass-fabrication of graphene-based devices. To address these issues, we combined an array of growth approaches and characterization resources to investigate several innovative and synergistic approaches for the synthesis of high quality graphene films on technologically relevant substrate (SiC and metals). Our work focused on developing the fundamental scientific understanding necessary to generate large-area graphene films that exhibit highly uniform electronic properties and record carrier mobility, as well as developing techniques to transfer graphene onto other substrates.
Pan, Wei; Ohta, Taisuke; Biedermann, Laura Butler; Gutierrez, Carlos; Nolen, C. M.; Howell, Stephen Wayne; Beechem Iii, Thomas Edwin; McCarty, Kevin F.; Ross, Anthony Joseph, III
Hydrogen Storage Properties of Magnesium Base Nanostructured Composite Materials
In this work, nanostructured composite materials have been synthesized using the mechanical alloying process. The new materials produced have been investigated by X-ray diffraction (XRD), transition electron microscope (TEM), scanning electron microscope (SEM) and electron energy dispersion spectrum (EDS) for their phase compositions, crystal structure, grain size, particle morphology and the distribution of catalyst element. Hydrogen storage capacities and the hydriding-dehydriding kinetics of the new materials have been measured at different temperatures using a Sieverts apparatus. It is observed that mechanical alloying accelerates the hydrogenation kinetics of the magnesium based materials at low temperature, but a high temperature must be provided to release the absorbed hydrogen from the hydrided magnesium based materials. It is believed that the dehydriding temperature is largely controlled by the thermodynamic configuration of magnesium hydride. Doping Mg-Ni nano/amorphous composite materials with lanthanum reduces the hydriding and dehydriding temperature. Although the stability of MgH2 can not be easily reduced by ball milling alone, the results suggest the thermodynamic properties of Mg-Ni nano/amorphous composite materials can be alternated by additives such as La or other effective elements. Further investigation toward understanding the mechanism of additives will be rewarded.
Graphene Penetrates Cell Membranes through Atomically Thin ...
About this Abstract. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium , Biological Materials Science Symposium. Presentation Title, Graphene ...
Bilayer Graphene Gets a Bandgap Print Bilayer Graphene Gets a Bandgap Print Graphene is the two-dimensional crystalline form of carbon whose extraordinary electron mobility and other unique features hold great promise for nanoscale electronics and photonics. But without a bandgap, graphene's promise can't be realized. As with monolayer graphene, bilayer graphene also has a zero bandgap and thus behaves like a metal. But a bandgap can be introduced if an electric displacement field is applied to the two layers; the material then behaves like a semiconductor. A team of researchers from Berkeley has engineered a bandgap in bilayer graphene that can be precisely controlled from 0 to 250 meV. With precision control of its bandgap over a wide range, plus independent manipulation of its electronic states through electrical doping, dual-gated bilayer graphene becomes a remarkably flexible tool for nanoscale electronic devices.
Functionalized Graphene Sheets as Molecular Templates for Controlled Nucleation and Self-Assembly of Metal Oxide-Graphene Nanocomposites
Graphene sheets have been extensively studied as a key functional component of graphene-based nanocomposites for electronics, energy, catalysis,and sensing applications. However, fundamental understanding of the interfacial binding and nucleation processes at graphene surfaces remains lacking, and the range of controlled structures that can be produced are limited. Here, by using a combination of theoretical and experimental approaches, we demonstrate that functionalized graphene sheets (FGS) can function as a new class of molecular templates to direct nucleation and self-assembly and produce novel, three-dimensional nanocomposite materials. Two key aspects are demonstrated: First, the functional groups on FGS surface determine the nucleation energy, and thus control the nucleation sites and nucleation density, as well as the preferred crystalline phases. Second, FGS can function as a template to direct the self-assembly of surfactant micelles and produce ordered, mesoporous arrays of crystalline metal oxides and composites.
Li, Xiaolin; Qi, Wen N.; Mei, Donghai; Sushko, Maria L.; Aksay, Ilhan A.; Liu, Jun
Argonne CNM Highlight: Nanopatterning of Graphene
Nanopatterning of Graphene Nanopatterning of Graphene Hydrogen-passivated graphene Hydrogen passivated graphene imaged and patterned at the atomic scale with STM CNM users from Politecnico di Milano in Italy, working collaboratively with researchers in the Electronic & Magnetic Materials & Devices Group, have demonstrated the reversible and local modification of the electronic properties of graphene by hydrogen passivation and subsequent electron-stimulated hydrogen desorption with a scanning tunneling microscope (STM) tip. Graphene is a nearly ideal two-dimensional conductor consisting of a single sheet of hexagonally packed carbon atoms. The hydrogen passivation modifies graphene's electronic properties, opening a gap in the local density of states. The insulating state is reversed by
Effective material parameter retrieval for thin sheets: theory and application to graphene, thin silver films, and single-layer metamaterials
An important tool in the field of metamaterials is the extraction of effective material parameters from simulated or measured scattering parameters of a sample. Here we discuss a retrieval method for thin-film structures that can be approximated by a two-dimensional scattering sheet. We determine the effective sheet conductivity from the scattering parameters and we point out the importance of the magnetic sheet current to avoid an overdetermined inversion problem. Subsequently, we present two applications of the sheet retrieval method. First, we determine the effective sheet conductivity of thin silver films and we compare the resulting conductivities with the sheet conductivity of graphene. Second, we apply the method to a cut-wire metamaterial with an electric dipole resonance. The method is valid for thin-film structures such as two-dimensional metamaterials and frequency-selective surfaces and can be easily generalized for anisotropic or chiral media.
Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas
Compendium of Material Composition Data for Radiation Transport Modeling
Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library file or mechanism for revising the data in a consistent and traceable manner. The authors of this revision have addressed that problem by first compiling all of the information (i.e., numbers and references) for all the materials into a single database, maintained at PNNL, that was then used as the basis for this document.
McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert
DOE/MSU composite material fatigue database: Test methods, materials, and analysis
This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.
Mandell, J.F.; Samborsky, D.D. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering
Ultrathin Planar Graphene Supercapacitors
With the advent of atomically thin and flat layers of conducting materials such as graphene, new designs for thin film energy storage devices with good performance have become possible. Here, we report an in-plane fabrication approach for ultrathin supercapacitors based on electrodes comprised of pristine graphene and multi-layer reduced graphene oxide. The in-plane design is straightforward to implement and exploits efficiently the surface of each graphene layer for energy storage. The open architecture and the effect of graphene edges enable even the thinnest of devices, made from as grown 1-2 graphene layers, to reach specific capacities up to 80 Fcm-2. While, much higher (394 Fcm-2) specific capacities are observed in case of multi-layered graphene oxide electrodes, owing to the better utilization of the available electrochemical surface area. The performances of devices with pristine as well as thicker graphene based structures are examined using a combination of experiments and model calculations. The demonstrated all solid-state supercapacitors provide a prototype for a broad range of thin-film based energy storage devices.
Huang, Jingsong [ORNL; Meunier, Vincent [ORNL; Sumpter, Bobby G [ORNL; Ajayan, Pullikel M [Rice University; Yoo, Jung Joon [KAIST, Daejeon, Republic of Korea; Balakrishnan, Kaushik [Rice University; Srivastava, Anchal [Rice University; Conway, Michelle [Rice University; Reddy, Arava Leela Mohan [Rice University; Yu, Jin [Rice University; Vajtai, Robert [Rice University
Flame retardancy effects of graphene nanoplatelet/carbon nanotube hybrid membranes on carbon fiber reinforced epoxy composites
Carbon nanotube/graphene nanoplatelet (MWCNT/GNP) hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore ...
Dongxian Zhuo, Rui Wang, Lixin Wu, Yanhua Guo, Lin Ma, Zixiang Weng, Jinyu Qi
Present and Future Automotive Composite Materials Research Efforts at DOE
Automobiles of the future will be forced to travel fi.uther on a tank of fuel while discharging lower levels of pollutants. Currently, the United States uses in excess of 16.4 million barrels of petroleum per day. Sixty-six percent of that petroleum is used in the transportation of people and goods. Automobiles currently account for just under two-thirds of the nation's gasoline consumptio~ and about one-third of the total United States energy usage. [1] By improving transportation related fiel efficiency, the United States can lessen the impact that emissions have on our environment and provide a cleaner environment for fiture generations. In 1992, The Department of Energy's (DOE) Office of Transportation Materials completed a comprehensive program plan entitled, The Lightweight MateriaIs (LWko Multi-Year Program Plan, for the development of technologies aimed at reducing vehicle mass [2]. This plan was followed in 1997 by the more comprehensive Office of Advanced Automotive Technologies research and development plan titled, Energy Eficient Vehicles for a Cleaner Environment [3] which outlines the department's plans for developing more efficient vehicles during the next ~een years. Both plans identi~ potential applications, technology needs, and R&D priorities. The goal of the Lightweight Materials Program is to develop materials and primary processing methods for the fabrication of lighter weight components which can be incorporated into automotive systems. These technologies are intended to reduce vehicle weight, increase fuel efficiency and decrease emissions. The Lightweight Materials program is jointly managed by the Department of Energy(DOE) and the United States Automotive Materials Partnership (USAMP). Composite materiak program work is coordinated by cooperative research efforts between the DOE and the Automotive Composites Consortium (ACC).
Warren, C.D.
Pressure-reaction synthesis of titanium composite materials
A pressure-reaction synthesis process for producing increased stiffness and improved strength-to-weight ratio titanium metal matrix composite materials comprising exothermically reacting a titanium powder or titanium powder alloys with non-metal powders or gas selected from the group consisting of C, B, N, BN, B.sub.4 C, SiC and Si.sub.3 N.sub.4 at temperatures from about 900.degree. to about 1300.degree. C., for about 5 to about 30 minutes in a forming die under pressures of from about 1000 to 5000 psi.
Oden, Laurance L. (Albany, OR); Ochs, Thomas L. (Albany, OR); Turner, Paul C. (Albany, OR)
Composite material including nanocrystals and methods of making
Temperature-sensing compositions can include an inorganic material, such as a semiconductor nanocrystal. The nanocrystal can be a dependable and accurate indicator of temperature. The intensity of emission of the nanocrystal varies with temperature and can be highly sensitive to surface temperature. The nanocrystals can be processed with a binder to form a matrix, which can be varied by altering the chemical nature of the surface of the nanocrystal. A nanocrystal with a compatibilizing outer layer can be incorporated into a coating formulation and retain its temperature sensitive emissive properties
Bawendi, Moungi G. (Boston, MA); Sundar, Vikram C. (New York, NY)
Graphene based transistors: physics, status and future perspectives
Graphene is a single-atom thick layer of graphite, which is one of the well known allotropes of carbon. While Graphene is a 2-D material, it can be either rolled-up to form carbon nanotubes (CNT) or simply patterned to form graphene nano-ribbons (GNR), ... Keywords: carbon nanotubes, cnfet, gnr-fet., graphene
Kaustav Banerjee; Yasin Khatami; Chaitanya Kshirsagar; S. Hadi Rasouli
Lightweight Impact-Resistant Composite Materials: Lessons from Mantis Shrimp
83 Composite Layup Synthesis and Mechanicalover conventional layup patterns in many materialin real time. Composite Layup Synthesis and Mechanical
Milliron, Garrett
Analytical Theory of Graphene Nanoribbon Transistors
Graphene has emerged as one of the most promising materials to address scaling challenges in the post silicon era. A simple model for graphene nanoribbon field-effect transistors (GNRFETs) is developed for treating the effects of edge bond relaxation, ... Keywords: Graphene nanoribbons, analytical model, edge bond relaxation, third nearest neighbor interaction, edge scattering
Pei Zhao; Mihir Choudhury; Kartik Mohanram; Jing Guo
Fatigue of Composite Materials and Substructures for Wind Turbine Blades
This report presents the major findings of the Montana State University Composite Materials Fatigue Program from 1997 to 2001, and is intended to be used in conjunction with the DOE/MSU Composite Materials Fatigue Database. Additions of greatest interest to the database in this time period include environmental and time under load effects for various resin systems; large tow carbon fiber laminates and glass/carbon hybrids; new reinforcement architectures varying from large strands to prepreg with well-dispersed fibers; spectrum loading and cumulative damage laws; giga-cycle testing of strands; tough resins for improved structural integrity; static and fatigue data for interply delamination; and design knockdown factors due to flaws and structural details as well as time under load and environmental conditions. The origins of a transition to increased tensile fatigue sensitivity with increasing fiber content are explored in detail for typical stranded reinforcing fabrics. The second focus of the report is on structural details which are prone to delamination failure, including ply terminations, skin-stiffener intersections, and sandwich panel terminations. Finite element based methodologies for predicting delamination initiation and growth in structural details are developed and validated, and simplified design recommendations are presented.
Disorder-free sputtering method on graphene
Deposition of various materials onto graphene without causing any disorder is highly desirable for graphene applications. Especially, sputtering is a versatile technique to deposit various metals and insulators for spintronics, and indium tin oxide to make transparent devices. However, the sputtering process causes damage to graphene because of high energy sputtered atoms. By flipping the substrate and using a high Ar pressure, we demonstrate that the level of damage to graphene can be reduced or eliminated in dc, rf, and reactive sputtering processes.
Qiu Xue Peng; Shin Young Jun; Niu Jing; Kulothungasagaran, Narayanapillai [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore); Kalon, Gopinadhan; Yang, Hyunsoo [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore); Graphene Research Centre, National University of Singapore, 117546 (Singapore); Qiu Caiyu [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637616 (Singapore); Yu Ting [Graphene Research Centre, National University of Singapore, 117546 (Singapore); Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637616 (Singapore)
conductive paper for energy-storage devices" Proceedings ofChemical Capacitive Energy Storage" Advanced Materials 2011,conductive paper for energy-storage devices" Proceedings of
Casimir interactions between graphene sheets and metamaterials
The Casimir force between graphene sheets and metamaterials is studied. Theoretical results based on the Lifshitz theory for layered, planar, two-dimensional systems in media are presented. We consider graphene-graphene, graphene-metamaterial, and metal-graphene-metamaterial configurations. We find that quantum effects of the temperature-dependent force are not apparent until the submicron range. In contrast to results with bulk dielectric and bulk metallic materials, no Casimir repulsion is found when graphene is placed on top of a magnetically active metamaterial substrate, regardless of the strength of the low-frequency magnetic response. In the case of the metal-graphene-metamaterial setting, repulsion between the metamaterial and the metal-graphene system is possible only when the dielectric response from the metal contributes significantly.
Drosdoff, D.; Woods, Lilia M. [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States)
Nano-scaled graphene platelets with a high length-to-width aspect ratio
This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.
Zhamu, Aruna (Centerville, OH); Guo, Jiusheng (Centerville, OH); Jang, Bor Z. (Centerville, OH)
M1, Material and Electronic Properties of CVD Graphene Grown on ...
GG6, Thermomagnetic Transport Properties of (AgxSbTex/2+1)15(GeTe)85 Thermoelectric Materials · GG7, Thermoelectric Properties of Sn-Rich Pb1?xSnx
Materials characterization center workshop on compositional and microstructural analysis of nuclear waste materials. Summary report
The purpose of the Workshop on Compositional and Microstructural Analysis of Nuclear Waste Materials, conducted November 11 and 12, 1980, was to critically examine and evaluate the various methods currently used to study non-radioactive, simulated, nuclear waste-form performance. Workshop participants recognized that most of the Materials Characterization Center (MCC) test data for inclusion in the Nuclear Waste Materials Handbook will result from application of appropriate analytical procedures to waste-package materials or to the products of performance tests. Therefore, the analytical methods must be reliable and of known accuracy and precision, and results must be directly comparable with those from other laboratories and from other nuclear waste materials. The 41 participants representing 18 laboratories in the United States and Canada were organized into three working groups: Analysis of Liquids and Solutions, Quantitative Analysis of Solids, and Phase and Microstructure Analysis. Each group identified the analytical methods favored by their respective laboratories, discussed areas needing attention, listed standards and reference materials currently used, and recommended means of verifying interlaboratory comparability of data. The major conclusions from this workshop are presented.
Daniel, J.L.; Strachan, D.M.; Shade, J.W.; Thomas, M.T.
Compositional Analysis of Water-Soluble Materials in Corn Stover
Corn stover is one of the leading feedstock candidates for commodity-scale biomass-to-ethanol processing. The composition of water-soluble materials in corn stover has been determined with greater than 90% mass closure in four of five representative samples. The mass percentage of water-soluble materials in tested stover samples varied from 14 to 27% on a dry weight basis. Over 30 previously unknown constituents of aqueous extracts were identified and quantified using a variety of chromatographic techniques. Monomeric sugars (primarily glucose and fructose) were found to be the predominant water-soluble components of corn stover, accounting for 30-46% of the dry weight of extractives (4-12% of the dry weight of feedstocks). Additional constituents contributing to the mass balance for extractives included various alditols (3-7%), aliphatic acids (7-21%), inorganic ions (10-18%), oligomeric sugars (4-12%), and a distribution of oligomers tentatively identified as being derived from phenolic glycosides (10-18%).
Chen, S. F.; Mowery, R. A.; Scarlata, C. J.; Chambliss, C. K.
Preparation, characterization, thermal, and flame-retardant properties of green silicon-containing epoxy/functionalized graphene nanosheets composites
In this investigation, silane was grafted onto the surface of graphene nanosheets (GNSs) through free radical reactions, to form Si-O-Et functional groups that can undergo the sol-gel reaction. To improve the compatibility between the polymer matrix ...
Ming-Yuan Shen, Chen-Feng Kuan, Hsu-Chiang Kuan, Chia-Hsun Chen, Jia-Hong Wang, Ming-Chuen Yip, Chin-Lung Chiang
Atomistic Simulation of Graphene-Polyurethane Nanocomposite for Use in Ballistic Applications
Exposure to high impact velocity is the principle limiting factor of material performance in ballistic applications for use in civilian and defense industries. Graphene has emerged as a material of scientific interest due to its exceptional mechanical and thermal properties. When incorporated appropriately in a polymer matrix, graphene can significantly improve properties of polymers at small loading, while preserving the integrity of the polymer. Graphene based polymer nanocomposites provide a novel approach for material design for ballistic applications. The reliability of graphene/polymer nanocomposites on end use applications depends on understanding the effect of structure-property relationship of nanocomposite. A first approach to engineering nanocomposite for ballistic applications requires thorough understanding of physical properties change with incorporation of nanofillers in polymer matrix. One significant class of properties tremendously affected by inclusion of nanofiller is thermodynamic properties. Therefore, a first investigative study, we explore non-linear elastic behavior of graphene using first principle method, specifically Density-Functional Theory (DFT), and atomistic simulation. Using DFT, we calculated the equation of state (EOS) and elastic constants of graphene. The results are in agreement with experimental and other theoretical studies using DFT. However, accuracy of atomistic simulations is limited by empirical potentials. Nevertheless, general anisotropic, non-linear mechanical behavior of graphene is evident on both approaches. Additionally we use molecular dynamics (MD) simulations to study effect of graphene nanofiller on thermo?mechanical properties of polyurethane. We have calculated thermodynamic, structural and mechanical properties of the amorphous polyurethane and its graphene nanocomposite. Our results show significant enhancement of thermal-mechanical properties. The final part of this dissertation, we used non-equilibrium molecular dynamics (NEMD) simulations to investigate dynamic response behavior of polyurethane and its graphene nanocomposite. Calculation of Hugoniot states of polyurethane agrees with experimental studies. However, a phase change phenomenon observed in experimental work was not visible in the present work. This is due to bond breaking and formation, which is a clear characterization of phase changes. Graphene-polyurethane nanocomposites demonstrate similar shock wave propagation illustrating characteristics of impeding shock wave when subjected to different particle velocities. This is due to graphene inducing stress concentrations in the composite, which may increase yield strength.
Njoroge, Jean L
First Industrial Nanostructured WC-Co Composite Materials
Morphological Forms of Phosphogypsum Depending on Modification Approaches in Using as Mineral Filler for Polymer Composites · Nanostructured ...
Surface functionalization of graphene devices
Graphene, a zero-gap semiconductor with massless charge carriers, is emerging as an amazing material for future electronics, due to its outstanding electrical and mechanical performances. However, the lack of a bandgap ...
Zhang, Xu, S.M. Massachusetts Institute of Technology
Graphene Energy | Open Energy Information
Graphene Energy Graphene Energy Jump to: navigation, search Name Graphene Energy Place Austin, Texas Sector Carbon Product Graphene develops nano-technology based ultracapacitors for energy storage using a unique form of carbon, called graphene, for electrode material. Coordinates 30.267605°, -97.742984° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":30.267605,"lon":-97.742984,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Functionalization of Graphene and Graphene Oxide for Biosensing and Imaging
Recent advances in our group about graphene biofunctionalization are discussed. In particular, the functionalization of graphene and graphene oxide, biosensing and bioimaging by using graphene-based nanomaterials, and some fundamental studies of graphene and graphene oxide have been summarized.
Li, Zhaohui; Wang, Ying; Du, Dan; Tang, Zhiwen; Wang, Jun; Lin, Yuehe
Development and characterization of renewable resource- structural composite materials
Applications." Biopolymers from Renewable Resources, D. L.blends and composites from renewable resources." Progress inadhesive from a renewable plant polymer: characteristics and
Cutter, Andrea Gillian
Fracture Study of Polymer and Polymeric Composite Materials Using ...
Abstract Scope, Wind turbines are subject to complex loading conditions during service. Since turbine blades are usually fabricated from polymeric composite ...
Activated carbon fiber composite material and method of making
An activated carbon fiber composite for separation and purification, or catalytic processing of fluids is described. The activated composite comprises carbon fibers rigidly bonded to form an open, permeable, rigid monolith capable of being formed to near-net-shape. Separation and purification of gases are effected by means of a controlled pore structure that is developed in the carbon fibers contained in the composite. The open, permeable structure allows the free flow of gases through the monolith accompanied by high rates of adsorption. By modification of the pore structure and bulk density the composite can be rendered suitable for applications such as gas storage, catalysis, and liquid phase processing.
Burchell, Timothy D. (Oak Ridge, TN); Weaver, Charles E. (Knoxville, TN); Chilcoat, Bill R. (Knoxville, TN); Derbyshire, Frank (Lexington, KY); Jagtoyen, Marit (Lexington, KY)
Lightweight Composite Materials for Fire Control and Prevention in ...
Abstract Scope, Trelleborg Offshore is exploring the potential uses of current offshore composite foams ... Structural Health Monitoring of Wind Turbine Blades.
Titanium composite material for oil and gas industry applications
About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Corrosion and Corrosion Protection of Materials in the Oil and Gas Industry.
Creation Technology of New Material by Composite Plating Method
About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Advanced Manufacturing Technologies. Presentation Title, Creation ...
Development of a test method for composite materials energy absorption: corrugated specimens
Group of the CMH-17 (Composite Materials Handbook, formerly known as MIL-HDBK-17), which comprises Materials Handbook, previously MIL-HDBK-17), and Dr. Larry Ilcewicz (FAA) for his vision on composites., "Energy management working group activities", Proceedings of the 48th MIL-HDBK- 17 Coordination Meeting
Feraboli, Paolo
Mechanical and Tribological Properties of AA2124-Graphene Self ...
Addition of graphene significantly increased the compressive strength and hardness of the composites, while poor results were obtained for the ductility at room ...
Synthesis and Characterization of Hydroxyapatite-graphene Oxide ...
In an effort to address these issues, synthesis of hydroxyapatite-graphene oxide ( HA-GO) nano composites has been carried. GO is selected as a reinforcement ...
ZnS-Graphene nanocomposite: Synthesis, characterization and optical properties
A ZnS-Graphene nanocomposite was prepared by a facile one-step hydrothermal method using zinc nitrate hexahydrate, ethylenediamine and carbon disulfide as precursors, graphene oxide as a template. The composite was characterized by X-ray power diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Fourier transform infrared, Raman spectra and fluorescence spectroscopy. The results show that graphene oxide was reduced to graphene in the hydrothermal reaction process. Simultaneously, the graphene sheets in the composite are exfoliated and decorated with ZnS nanoparticles. Furthermore, Raman and fluorescence properties of the composite were observed. ZnS-Graphene nanocomposite displays surface-enhanced Raman scattering activity for graphene oxide, and fluorescence enhancement property compared with pure ZnS sample. - Graphical abstract: Approach of reaction makes the reduction of grapheme oxide and the deposition of Zns on the grapheme sheets occur simultaneously and overcomes the aggregation of the grapheme sheets and Zns. Highlights: Black-Right-Pointing-Pointer Graphene oxide is reduced to graphene in the hydrothermal reaction process. Black-Right-Pointing-Pointer ZnS nanoparticles are attached onto the almost transparent graphene sheets. Black-Right-Pointing-Pointer ZnS-Graphene system shows surface-enhanced Raman scattering (SERS) activity. Black-Right-Pointing-Pointer ZnS-Graphene system displays relatively better fluorescence property than pure ZnS.
Pan Shugang [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Liu Xiaoheng, E-mail: firstname.lastname@example.com [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China)
Argonne CNM Highlight: Graphene Research at the Center for Nanoscale
Graphene Research at the Center for Nanoscale Materials Graphene Research at the Center for Nanoscale Materials graphene research The 2010 Nobel Prize in Physics was recently awarded to Andre Geim and Konstantin Novoselov from the University of Manchester "for groundbreaking experiments regarding the two-dimensional material graphene." Graphene is an extraordinary material made up of hexagonally packed carbon atoms that are sp2 bonded. A sheet of graphene is only one atom thick making it nature's version of an ideal two-dimensional material. At the Center for Nanoscale Materials we are exploring state-of-the-art synthesis, characterization, processing, and novel applications of graphene. With the highest resolution microscopes we are able to characterize the structural, electronic, and chemical properties of
The Development of Low-Cost Integrated Composite Seal for SOFC: Materials and Design Methodologies
This report summarizes the work conducted by UConn SOFC seal development team during the Phase I program and no cost extension. The work included composite seal sample fabrication, materials characterizations, leak testing, mechanical strength testing, chemical stability study and acoustic-based diagnostic methods. Materials characterization work revealed a set of attractive material properties including low bulk permeability, high electrical resistivity, good mechanical robustness. Composite seal samples made of a number of glasses and metallic fillers were tested for sealing performance under steady state and thermal cycling conditions. Mechanical testing included static strength (pull out) and interfacial fracture toughness measurements. Chemically stability study evaluated composite seal material stability after aging at 800 C for 168 hrs. Acoustic based diagnostic test was conducted to help detect and understand the micro-cracking processes during thermal cycling test. The composite seal concept was successfully demonstrated and a set of material (coating composition & fillers) were identified to have excellent thermal cycling performance.
Xinyu Huang; Kristoffer Ridgeway; Srivatsan Narasimhan; Serg Timin; Wei Huang; Didem Ozevin; Ken Reifsnider
Raman Nanometrology of Graphene
13 Optical image of the graphene layers. . . . . .Micro-Raman Spectroscopy of Grapheneand Graphene Multi-Layers . . . . Raman Spectroscopy
Calizo, Irene Gonzales
Virtual Mechanical Testing of Composites: From Materials to ...
First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... Different Generations of Gamma Prime Precipitates in a Commercial Nickel ...
Rubber Fiber-reinforced Composite Materials for Hydraulic Turbine
About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Advances in Hydroelectric Turbine Manufacturing and Repair. Presentation ...
Advanced Nanoparticle-Reinforced Polymer Composite Materials in ...
Jun 1, 2007... in such materials are analyzed and the relevance to damping is identified via both computational and experimental benchmarks; however, ...
ESS 2012 Peer Review - Next Generation Composite Materials for...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
purposes, materials with higher strengths, and lower densities that would allow the flywheel to spin faster are desirable. We have recently begun a project to develop new...
Study of Composite Materials Application for Horizontal Axis Wind ...
Since the specific velocity is directly related to the coefficient of power Cp of a wind rotor, this article presents a comparative study with different materials and ...
Raw Material." Angewandte Chemie International Edition , 44(Angewandte Makromolekulare Chemie, F. Vilaseca, Mendez, J.Die Angewandte Makromolekulare Chemie , [100] J. Gassan, and
Thermal Conduction in Graphene and Graphene Multilayers
E. , and Ju, Y. S. , " Heat conduction in novel electronicBalandin, A. A. , "Heat conduction in graphene: experimentalD. , "Simulation of heat conduction in suspended graphene
Ghosh, Suchismita
Graphene Transistors Fabricated via Transfer-Printing In Device Active-Areas
growth.5 However, to use graphene as the material for integrated circuits we need high-quality graphene. wafers. This paper reports a demonstration of a different approach to achieve high-quality graphene- printing (DCT), does not intend to put high-quality graphene everywhere on a large substrate but rather
Effect of high K dielectric on mobility of graphene FET
In order to overcome the limitation of Moore's law in recent years much attention has been focused on graphene as an alternative to silicon. In this paper different gate dielectric materials for use in graphene transistors is examined. Evaporated HfO2 ... Keywords: conductance, graphene, k dielectric, mobility
V. B. Sahu; P. G. Pawar; A. Gajarushi
Y1, Graphene Synthesis on C-Face and Si-Face 4H-SiC
About this Abstract. Meeting, 2009 Electronic Materials Conference. Symposium, Electronic Materials Conference. Presentation Title, Y1, Graphene Synthesis on ...
Synthesis and characterization of a nanocomposite of goethite nanorods and reduced graphene oxide for electrochemical capacitors
We report a one-step synthesis of a nanocomposite of goethite ({alpha}-FeOOH) nanorods and reduced graphene oxide (RGO) using a solution method in which ferrous cations serve as a reducing agent of graphite oxide (GO) to graphene and a precursor to grow goethite nanorods. As-prepared goethite nanorods have an average length of 200 nm and a diameter of 30 nm and are densely attached on both sides of the RGO sheets. The electrochemical properties of the nanocomposite were characterized by cyclic voltammetry (CV) and chronopotentiometry (CP) charge-discharge tests. The results showed that goethite/RGO composites have a high electrochemical capacitance of 165.5 F g{sup -1} with an excellent recycling capability making the material promising for electrochemical capacitors. - Graphical abstract: The reduced graphene oxide sheets are decorated with goethite nanorods. The as-prepared composite exhibits a high electrochemical capacitance with good recycling capability, which is promising for supercapacitor applications. Higlights: Black-Right-Pointing-Pointer Ferrous ions act as reductant of graphite oxide and precursor of goethite nanorods. Black-Right-Pointing-Pointer Goethite nanorods are attached on both sides of the reduced graphene oxide sheets. Black-Right-Pointing-Pointer Composite exhibits a high specific capacitance and a good recycling capability. Black-Right-Pointing-Pointer Composite is promising for supercapacitor applications.
Shou Qingliang [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Cheng Jipeng, E-mail: email@example.com [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang Li, E-mail: email@example.com [Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092 Zurich (Switzerland); Nelson, Bradley J. [Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092 Zurich (Switzerland); Zhang Xiaobin [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)
Fluorescent single walled nanotube/silica composite materials
Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.
Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.
Improved method and composition for immobilization of waste in cement-based material
A composition and method for fixation or immobilization of aqueous hazardous waste material in cement-based materials (grout) is disclosed. The amount of drainable water in the cured grout is reduced by the addition of an ionic aluminum compound to either the waste material or the mixture of waste material and dry-solid cement- based material. This reduction in drainable water in the cured grout obviates the need for large, expensive amounts of gelling clays in grout materials and also results in improved consistency and properties of these cement-based waste disposal materials.
Tallent, O.K.; Dodson, K.E.; McDaniel, E.W.
Hot Corrosion of SiC-based Ceramic Matrix Composite Materials
The hot corrosion performance of monolithic SiC as well as SiC-SiC composites were characterized. Coatings of C and BN on the monolithic materials were ...
ARRA Material Handling Equipment Composite Data Products: Data through Quarter 2 of 2012
This presentation from the U.S. Department of Energy's National Renewable Energy Laboratory includes American Recovery and Reinvestment Act (ARRA) fuel cell material handling equipment composite data products for data through the second quarter of 2012.
Kurtz, J.; Sprik, S.; Ramsden, T.; Ainscough, C.; Saur, G.
Piezoelectric-based in-situ damage detection of composite materials for structural health monitoring systems
Cost-effective and reliable damage detection is critical for the utilization of composite materials. This thesis presents the conclusions of an analytical and experimental survey of candidate methods for in-situ damage ...
Kessler, Seth Stovack, 1977-
ARRA Material Handling Equipment Composite Data Products: Data Through Quarter 4 of 2012
This presentation from the U.S. Department of Energy's National Renewable Energy Laboratory includes American Recovery and Reinvestment Act (ARRA) fuel cell material handling equipment composite data products for data through the fourth quarter of 2012.
Kurtz, J.; Sprik, S.; Ainscough, C.; Saur, G.; Post, M.; Peters, M.; Ramsden, T.
Bibliometric trend analysis on global graphene research
Graphene is a rising star as one of the promising materials with many applications. Its global literature increased fast in recent years. In this work, bibliometric analysis and knowledge visualization technology were applied to evaluate global scientific ... Keywords: Bibliometric analysis, Co-authorship, Co-words, Graphene, Knowledge mapping, Research trend
Peng Hui Lv; Gui-Fang Wang; Yong Wan; Jia Liu; Qing Liu; Fei-Cheng Ma
Composite materials and bodies including silicon carbide and titanium diboride and methods of forming same
Methods of forming composite materials include coating particles of titanium dioxide with a substance including boron (e.g., boron carbide) and a substance including carbon, and reacting the titanium dioxide with the substance including boron and the substance including carbon to form titanium diboride. The methods may be used to form ceramic composite bodies and materials, such as, for example, a ceramic composite body or material including silicon carbide and titanium diboride. Such bodies and materials may be used as armor bodies and armor materials. Such methods may include forming a green body and sintering the green body to a desirable final density. Green bodies formed in accordance with such methods may include particles comprising titanium dioxide and a coating at least partially covering exterior surfaces thereof, the coating comprising a substance including boron (e.g., boron carbide) and a substance including carbon.
Lillo, Thomas M.; Chu, Henry S.; Harrison, William M.; Bailey, Derek
Using Spiral Notch Torsion Test to Evaluate Fracture Toughness of Structural Materials and Polymeric Composites
Spiral Notch Torsion Test (SNTT) was developed recently to measure the intrinsic fracture toughness (KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45 pitch. The KIC values and the associated energy release rate are obtained with the aid of a three-dimensional finite-element evaluation. The SNTT method is uniquely suitable for testing a wide variety of structural materials, including others such as ceramics, graphite, concrete, polymeric composites, and for bi-material interface fracture toughness evaluation. The SNTT test results for these structural materials and polymeric composite are demonstrated in this paper. These results demonstrated that SNTT has great potential in structural materials and polymeric composites testing, which can provide useful information for design and fabrication of structural components.
Wang, Jy-An John [ORNL; Tan, Ting [ORNL
Active, polymer-based composite material implementing simple shear
A novel active material for controllable, high work density applications was designed, fabricated, analyzed, and tested. This active material uses a lens-shaped element to implement simple shear motion with gas pressure actuation. The lens element is a bladder-filled Kevlar fabric embedded in a polyurethane matrix. The polyurethane's hyperelastic material parameters were found by experiment and estimated by numerical analysis. The Ogden material constant set found shows good agreement within the shear actuator's working range. A fabricated, single-element shear actuator reached 34.2% free shear strain when pressurized to 1.03 MPa. A unitary shear actuator was modeled as were single-acting and dual-acting shear actuator arrays so that solitary and multi-cell behaviors were estimated. Actuator work performance and power from nonlinear finite element analysis found conventional work density is 0.2289 MJ/m3 and 0.2482 MJ/m3, for the singleacting and double-acting shear actuator, respectively. Scientific work densities are 0.0758 MJ/m3 and 0.0375 MJ/m3, for single-acting and double-acting shear actuators, respectively. Calculation shows the volumetric power for a single-acting shear actuator is 0.4578 MW/m3 and 0.4964 MW/m3 for the double-acting shear actuator. Finally, a nastic actuator is applied to twist a generic structural beam. The nasticmaterial actuated structure has an advantage over conventional actuator systems. Work per unit volume for nastic materials is 2280~8471% higher than conventional, discrete actuators that use electric motors. When compared by work per unit mass, this nastic actuator is 2592~13900% better than conventional actuator because nastic actuator is made from lighter materials and it distributes the actuation throughout the structure, which eliminates connecting components. The nastic actuator's volumetric power is 2217~8602% higher than conventional actuators. Finally, the nastic actuator is 2656~14269% higher than conventional actuators for power per unit mass.
Lee, Sang Jin
An inpile experiment is currently underway wherein specimens comprised of a newly developed material are being irradiated at Idaho National Laboratory's Advanced Test Reactor (ATR) in conjunction with Utah State University under the auspices of the ATR National Scientific User Facility. This paper provides the thermophysical properties of this new material measured prior to irradiation. After the irradiation campaign is complete, the thermophysical properties of the specimens will be measured and compared to the preirradiation values. A finite-element model was constructed to predict bounding specimen temperatures during irradiation. Results from the thermal hydraulic modeling, including the steady-state temperatures of the specimens within sealed capsules, are presented. After the irradiation campaign is completed, best-estimate thermal predictions will be performed for the individual specimens using the actual as-run irradiation power levels.
Donna Post Guillen; W. David Swank; Heng Ban; Kurt Harris; Adam Zabriskie
Effects of Materials Parameters and Design Details on the Fatigue of Composite Materials for Wind Turbine Blades
This paper presents an analysis of the results of nine years of fatigue testing represented in the USDOE/Montana State University (DOE/MSU) Composite Materials Fatigue Database. The focus of the program has been to explore a broad range of glass-fiber-based materials parameters encompassing over 4500 data points for 130 materials systems. Significant trends and transitions in fatigue resistance are shown as the fiber content and fabric architecture are varied. The effects of structural details including ply drops, bonded stiffeners, and other geometries that produce local variations in fiber packing and geometry are also described. Fatigue tests on composite beam structures are then discussed; these show generally good correlation with coupon fatigue data in the database. Goodman diagrams for fatigue design are presented, and their application to predicting the service lifetime of blades is described.
Mandell, J.F.; Samborsky, D.D.; Sutherland, H.J.
Direct Imaging of Soft?Hard Interfaces Enabled by Graphene
bates on a graphene sheet in a conventional TEM.14 As demonstrated here, the TEM imaging of molecular layers and interfaces between hard and soft materials can be
Defect in Graphene May Present Bouquet of Possibilities
A class of decorative, flower-like defects in the nanomaterial graphene could have potentially important effects on the material's already unique ...
Revealing the rapid isothermal growth of graphene on catalytic...
Materials Synthesis from Atoms to Systems Revealing the rapid isothermal growth of graphene on catalytic substrates July 01, 2013 Optical reflectivity tracks the rapid growth of...
Ion irradiation tolerance of graphene as studied by atomistic simulations
As impermeable to gas molecules and at the same time transparent to high-energy ions, graphene has been suggested as a window material for separating a high-vacuum ion beam system from targets kept at ambient conditions. However, accumulation of irradiation-induced damage in the graphene membrane may give rise to its mechanical failure. Using atomistic simulations, we demonstrate that irradiated graphene even with a high vacancy concentration does not show signs of such instability, indicating a considerable robustness of graphene windows. We further show that upper and lower estimates for the irradiation damage in graphene can be set using a simple model.
Ahlgren, E. H.; Lehtinen, O. [Department of Physics, University of Helsinki, P.O. Box 43, 00014 Helsinki (Finland); Kotakoski, J. [Department of Physics, University of Helsinki, P.O. Box 43, 00014 Helsinki (Finland); Department of Physics, University of Vienna, Boltzmanngasse 5, 1190 Wien (Austria); Krasheninnikov, A. V. [Department of Physics, University of Helsinki, P.O. Box 43, 00014 Helsinki (Finland); Department of Applied Physics, Aalto University, P.O. Box 1100, 00076 Aalto (Finland)
Controlling Graphene's Electronic Structure
Controlling Graphene's Electronic Structure Print Graphene, because of its unusual electron properties, reduced dimensionality, and scale, has enormous potential for use in...
Linear Graphene Plasmons
The coupling of the plasmon spectra of graphene and a nearby thick plasma is examined here in detail. The coupled modes include linear plasmons. Keywords: Graphene, plasmons, surface
N. J.M. Horing
Controlling Graphene's Electronic Structure Print Wednesday, 25 April 2007 00:00 Graphene, because of its unusual electron properties, reduced dimensionality, and scale, has...
Mesoporous carbon -Cr2O3 composite as an anode material for lithium ion batteries
Mesoporous carbon-Cr2O3 (M-C-Cr2O3) composite was prepared by co-assembly of in-situ formed phenolic resin, chromium precursor, and Pluronic block copolymer under acidic conditions, followed by carbonization at 750oC under Argon. The TEM results confirmed that the Cr2O3 nanoparticles, ranging from 10 to 20 nm, were well dispersed in the matrix of mesoporous carbon. The composite exhibited an initial reversible capacity of 710 mAh g-1 and good cycling stability, which is mainly due to the synergic effects of carbons within the composites, i.e. confining the crystal growth of Cr2O3 during the high temperature treatment step and buffering the volume change of Cr2O3 during the cycling step. This composite material is a promising anode material for lithium ion batteries.
Guo, Bingkun [ORNL; Chi, Miaofang [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL
A Cautionary Tale of Two Basis Sets and Graphene
Density functional theory is a leading approach for simulating materials. However, the basis set used in calculations can directly affect our understanding of a material. By comparing two basis sets for graphene, this highlights an important subtle point ... Keywords: Density functional theory, basis set, graphene, electronic structure, computational materials science, scientific computing
Derek Stewart
Composite Materials under Extreme Radiation and Temperature Environments of the Next Generation Nuclear Reactors
In the nuclear energy renaissance, driven by fission reactor concepts utilizing very high temperatures and fast neutron spectra, materials with enhanced performance that exceeds are expected to play a central role. With the operating temperatures of the Generation III reactors bringing the classical reactor materials close to their performance limits there is an urgent need to develop and qualify new alloys and composites. Efforts have been focused on the intricate relations and the high demands placed on materials at the anticipated extreme states within the next generation fusion and fission reactors which combine high radiation fluxes, elevated temperatures and aggressive environments. While nuclear reactors have been in operation for several decades, the structural materials associated with the next generation options need to endure much higher temperatures (1200 C), higher neutron doses (tens of displacements per atom, dpa), and extremely corrosive environments, which are beyond the experience on materials accumulated to-date. The most important consideration is the performance and reliability of structural materials for both in-core and out-of-core functions. While there exists a great body of nuclear materials research and operating experience/performance from fission reactors where epithermal and thermal neutrons interact with materials and alter their physio-mechanical properties, a process that is well understood by now, there are no operating or even experimental facilities that will facilitate the extreme conditions of flux and temperature anticipated and thus provide insights into the behaviour of these well understood materials. Materials, however, still need to be developed and their interaction and damage potential or lifetime to be quantified for the next generation nuclear energy. Based on material development advances, composites, and in particular ceramic composites, seem to inherently possess properties suitable for key functions within the operating envelope of both fission and fusion reactors. In advanced fission reactors composite materials are being designed in an effort to extend the life and improve the reliability of fuel rod cladding as well as structural materials. Composites are being considered for use as core internals in the next generation of gas-cooled reactors. Further, next-generation plasma-fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER) will rely on the capabilities of advanced composites to safely withstand extremely high neutron fluxes while providing superior thermal shock resistance.
Simos, N.
Crystallization Times of Ge-Te Phase Change Materials as a Function of Composition
The crystallization times of Ge-Te phase change materials with variable Ge concentrations (29.5-72.4 at. %) were studied. A very strong dependence of the crystallization time on the composition for as-deposited, amorphous films was confirmed, with a minimum for the stoichiometric composition GeTe. The dependence is weaker for melt-quenched, amorphous material and crystallization times are between one to almost four orders of magnitude shorter than for as-deposited materials. This is promising for applications because recrystallization from the melt-quenched phase is the relevant process for optical and solid state memory, and fast crystallization and weak dependence on compositional variations are desirable.
S Raoux; H Cheng; M Caldwell; H Wong
Graphene-based Electrochemical Energy Conversion and Storage: Fuel cells, Supercapacitors and Lithium Ion Batteries
Graphene has attracted extensive research interest due to its strictly 2-dimensional (2D) structure, which results in its unique electronic, thermal, mechanical, and chemical properties and potential technical applications. These remarkable characteristics of graphene, along with the inherent benefits of a carbon material, make it a promising candidate for application in electrochemical energy devices. This article reviews the methods of graphene preparation, introduces the unique electrochemical behavior of graphene, and summarizes the recent research and development on graphene-based fuel cells, supercapacitors and lithium ion batteries. In addition, promising areas are identified for the future development of graphene-based materials in electrochemical energy conversion and storage systems.
Hou, Junbo; Shao, Yuyan; Ellis, Michael A.; Moore, Robert; Yi, Baolian
Roadmap for Roadmap for Engineering Piezoelectricity in Graphene A Roadmap for Engineering Piezoelectricity in Graphene Doping this 'Miracle Material' May Lead to New Array of Nanoscale Devices, Simulations Reveal February 23, 2012 | Tags: Carver, Chemistry, Franklin, Materials Science Linda Vu, email@example.com, +1 510 495 2402 This illustration shows lithium atoms (red) dopped on graphene (black hexagons) and generating electricity. Graphic courtesy of Mitchell Ong, Stanford University. Some scientists refer to graphene as the "miracle material" of the 21st century. Composed of a single sheet of carbon atoms, this material is tougher than diamond, more conductive than copper, and has potential applications in a variety of technologies. Now with the help of supercomputers at the Department of Energy's
Graphene to Graphane: Novel Electrochemical Conversion
A novel electrochemical means to generate atomic hydrogen, simplifying the synthesis and controllability of graphane formation on graphene is presented. High quality, vacuum grown epitaxial graphene (EG) was used as starting material for graphane conversion. A home-built electrochemical cell with Pt wire and exposed graphene as the anode and cathode, respectively, was used to attract H+ ions to react with the exposed graphene. Cyclic voltammetry of the cell revealed the potential of the conversion reaction as well as oxidation and reduction peaks, suggesting the possibility of electrochemically reversible hydrogenation. A sharp increase in D peak in the Raman spectra of EG, increase of D/G ratio, introduction of a peak at ~2930 cm-1 and respective peak shifts as well as a sharp increase in resistance showed the successful hydrogenation of EG. This conversion was distinguished from lattice damage by thermal reversal back to graphene at 1000{\\deg}C.
Daniels, Kevin M; Zhang, R; Chowdhury, I; Obe, A; Weidner, J; Williams, C; Sudarshan, T S; Chandrashekhar, MVS
Structural characterization and structural/material similitude of hybrid composite tubes
Composites offer dramatically high stiffness to weight and strength to weight ratios which make them very desirable for use in offshore structures in deep water. In addition to high specific strength, composites offer the unique feature of being tailorable to the design. Hybrid composites, where multiple fiber types exist in a single matrix, further increase the functionality of composites by allowing the designer to add selectively stiffer, more costly fibers where the stresses are more critical and add less costly fibers where the stresses are less critical. This research focuses on the structural behavior of hybrid composite tubes when subjected to internal pressure, axial tension, and dynamic forces induced by wave and current interaction. A closed form, shear deformable shell code is developed to capture the strain state of hybrid composite tubes under axisymmetric loads and finite element analysis is used to determine the behavior of a composite tube subjected to dynamic loads and pressure loads. Scaling methods by means of structural/material similitude are also studied. For composites, these scaling laws depend not just on geometry, but also on constituent properties and the location and orientation of the constituents in the system. Through similitude, the behavior of tubes which cannot be tested easily can be verified using tubes which are easier to test or have already been tested.
Liggett, Glade Michael
Substrate-induced band gap opening in epitaxial graphene
Graphene has shown great application potential as the hostmaterial for next-generation electronic devices. However, despite itsintriguing properties, one of the biggest hurdles for graphene to beuseful as an electronic material is the lack of an energy gap in itselectronic spectra. This, for example, prevents the use of graphene inmaking transistors. Although several proposals have been made to open agap in graphene's electronic spectra, they all require complexengineering of the graphene layer. Here, we show that when graphene isepitaxially grown on SiC substrate, a gap of ~;0.26 eV is produced. Thisgap decreases as the sample thickness increases and eventually approacheszero when the number of layers exceeds four. We propose that the originof this gap is the breaking of sublattice symmetry owing to thegraphene-substrate interaction. We believe that our results highlight apromising direction for band gap engineering of graphene.
Zhou, S.Y.; Gweon, G.-H.; Fedorov, A.V.; First, P.N.; de Heer,W.A.; Lee, D.-H.; Guinea, F.; Castro Neto, A.H.; Lanzara, A.
Abstract-Finite element stiffness and consistent mass matrices are derived for helically wound, symmetrical composite tubes. The tubular element is considered to have constant cross-section and small deformations restricted to a plane. Each node has three degrees of freedom: axial and transverse displacement and rotation (slope oftransverse displacement). Shell theory and lamination theory are used to formulate element stiffness matrices. The stiffness and mass matrices derived from the helically wound tubular composite material are reduced to symmetrically laminated composite beam. The free vibration and natural frequency are investigated for five different materials: steel, aluminum, carbon/N5280, Kevlar-49/epoxy and graphite/epoxy composites and various layup configurations. One application of a rotating flexible beam is investigated. The dynamic model of the flexible rotating beam includes the coupled effect between the rigid body motion and the flexible motion. The inverse dynamic simulation is performed by a prescribed driving torque in the numerical simulation. The influence of flexibility on rigid body motion are presented and discussed. From the numerical results, the composite material strongly possesses the lower power consumption and the passive control in damping the vibration of the structure. INTRODUcnON
C. I. Chen; V. H. Mucino; E. J. Barbero
Testing and Analysis of Low Cost Composite Materials Under Spectrum Loading and High Cycle Fatigue Conditions
papers cited are available through the Sandia National Laboratories website: www.sandia.gov/Renewable_Energy/wind_energy-year experimental study of low- cost composite materials for wind turbine blades. Wind turbines are subjected to 109 in and potential interactions between failure modes. Wind turbine design codes typically assume a Miner's rule
Ceramic superconductor/metal composite materials employing the superconducting proximity effect
Superconducting composite materials having particles of superconducting material disposed in a metal matrix material with a high electron-boson coupling coefficient (.lambda.). The superconducting particles can comprise any type of superconductor including Laves phase materials, Chevrel phase materials, A15 compounds, and perovskite cuprate ceramics. The particles preferably have dimensions of about 10-500 nanometers. The particles preferably have dimensions larger than the superconducting coherence length of the superconducting material. The metal matrix material has a .lambda. greater than 0.2, preferably the .lambda. is much higher than 0.2. The metal matrix material is a good proximity superconductor due to its high .lambda.. When cooled, the superconductor particles cause the metal matrix material to become superconducting due to the proximity effect. In cases where the particles and the metal matrix material are chemically incompatible (i.e., reactive in a way that destroys superconductivity), the particles are provided with a thin protective metal coating. The coating is chemically compatible with the particles and metal matrix material. High Temperature Superconducting (HTS) cuprate ceramic particles are reactive and therefore require a coating of a noble metal resistant to oxidation (e.g., silver, gold). The proximity effect extends through the metal coating. With certain superconductors, non-noble metals can be used for the coating.
Holcomb, Matthew J. (Manhattan Beach, CA)
PML Develops Graphene Fabrication Capability
PML Develops Graphene Fabrication Capability. October 3, 2011. ... That further limits the growth of the graphene, we think. ...
Li-Ion Batteries from LiFePO4 Cathode and Anatase/Graphene Composite Anode for Stationary Energy Storage
Li-ion batteries based on LiFePO4 cathode and anatase TiO2/graphene anode were investigated for possible stationary energy storage application. Fine-structured LiFePO4 was synthesized by novel molten surfactant approach. Anatase TiO2/graphene nanocomposite was prepared via self assembly method. The full cell that operated at flat 1.6V demonstrated negligible fade after more than 700 cycles. The LiFePO4/TiO2 combination Li-ion battery is inexpensive, environmentally benign, safe and stable. Therefore, it can be practically applied as stationary energy storage for renewable power sources.
Choi, Daiwon; Wang, Donghai; Viswanathan, Vilayanur V.; Bae, In-Tae; Wang, Wei; Nie, Zimin; Zhang, Jiguang; Graff, Gordon L.; Liu, Jun; Yang, Zhenguo; Duong, Tien Q.
Molecular doping of graphene with ammonium groups
Successful doping of an electronic material entails the existence of stable dopant configurations that cause a shift in the Fermi level without altering significantly the electronic states of the host system. The selection of chemical groups that satisfy these conditions when adsorbed on graphene is still an open challenge. Here we show with first-principles calculations that ammonium groups meet the criteria of stable physisorption and efficient doping of graphene. We also describe processes of deactivation of ammonium dopants through their dissociation over graphene impurities or nanoribbon edges. Finally, we show that carbon nanotubes can be used to spatially confine the dopants and avert their edge-related de-activation.
Tsetseris, L. [Vanderbilt University; Pantelides, Sokrates T [ORNL
Compressive Creep Response of T1000G/RS-14 Graphite/Polycyanate Composite Materials
The response of a T1000G/RS-14 graphite/polycyanate composite material system to transverse compressive loads is quantified via experimentation. The primary objective of the work was to quantify the effects of process environment and test environment on the T1000G/RS-14 compressive creep response. Tests were conducted on both the neat resin and the composite material system. In addition to the creep tests, static compressive strength tests were conducted to define the stress-strain response. The creep behavior for the RS-14 resin was quantified by conducting a series of tests to study the effects of different process environments (air and nitrogen), different cure temperatures, and different test environments (air and vacuum). The combined effect on the RS-14 resin compressive creep of processing in nitrogen and testing under vacuum versus processing in air and testing in air was a 47% decrease in the creep strain after 2177 hr. The test environment appeared to have a greater effect on the resin creep than the process environment. Following the conclusion of the resin creep tests, composite transverse compressive creep tests were conducted. The composite creep test cylinder was post-cured in a nitrogen environment prior to machining test specimens and all tests were conducted in a vacuum environment. The series of tests investigated the effects of initial stress level and test temperature on the creep behavior. At the end of the 2000-hr tests at 275{degrees}F on specimens stressed at 10,000 psi, the nitrogen-processed and vacuum-tested conditions reduced the composite transverse compressive creep strain by 19% compared to processing in air and testing in air. The effects of process and test environment on the creep behavior are not as great for the composite system as they were for the neat resin, primarily because of the low resin content in the composite material system. At the 275{degrees}F test temperature there was a significant increase in the composite transverse compressive creep strain between the 6000-psi and 10,000-psi stress levels. Despite the reduction in creep strains due to processing in a nitrogen environment, dimensional stability of the T1000G/RS-14 composite at high transverse compressive stress levels and high temperatures may still be an issue when selecting this system for future applications.
Starbuck, J.M.
Testing and performance evaluation of T1000G/RS-14 graphite/polycyanate composite materials
The performance of a graphite fiber/polycyanate matrix composite material system, T1000G/RS-14, was evaluated by performing an extensive mechanical property test program. The test program included both static strength and long-term tests for creep, fatigue, and stress rupture. The system was evaluated at both ambient temperature and elevated temperatures. The specimens were machined from composite cylinders that had a unidirectional layup with all the fibers oriented in the hoop direction. The cylinders were fabricated using the wet-filament winding process. In general, the T1000G/RS-14 system demonstrated adequate static strengths for possible aerospace structural applications. The results from the static tests indicated that very high composite hoop tensile strengths can be achieved with this system at both ambient and elevated temperatures as high as 350{degree}F. However, in the long-term testing for compressive creep and tension-tension fatigue the results indicated a lower elevated temperature was required to minimize the risk of using this material system. Additional testing and analysis activities led to the selection of 275{degree}F as the desired temperature for future performance evaluation. Subsequent testing efforts for determining the resin and composite transverse compressive creep responses at 275{degrees}F indicated that excessive creep strain rates may still be a weakness of this system. In the long-term tests, sufficient data was generated from impregnated strand and composite ring stress-life testing, and composite ring tension-tension fatigue to determine failure probabilities for a given set of design requirements. The statistical analyses of the test data, in terms of determining failure probability curves, will be reported on in a separate report. However, it is expected that this material system will have a very low failure probability for stress rupture based on the collected stress-life data. Material responses that will require further investigation and/or possible performance improvements are fiber- direction tension-tension fatigue, and both resin and transverse composite compressive creep. Improvements in the creep performance or dimensional stability of this material system may ultimately depend on the test and/or process environment.
The electrochemical performance of ordered mesoporous carbon/nickel compounds composite material for supercapacitor
A series of high performance ordered mesoporous carbon/nickel compounds composites have been synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time. X-ray diffraction (XRD), N{sub 2} adsorption/desorption isotherms and transmission electron microscopy (TEM) are used to characterize the composites derived at the hydrothermal temperature of 125, 150, 175, 200, 250, 275 and 300 {sup o}C. The formation of nanosized nickel compounds, fully inside the mesopore system, was confirmed with XRD and TEM. An N{sub 2} adsorption/desorption isotherms measurements still revealed mesoporosity for the host/guest compounds. It is noteworthy that an OMC/nickel nitrate hydroxide hydrate composite (OMCN-150) exhibits more excellent performance. Based on the various hydrothermal temperatures of the composite, the capacitance of an OMCN-150 delivering the best electrochemical performance is about 2.4 (5 mV s{sup -1}) and 1.5 (50 mV s{sup -1}) times of the pristine OMC. The capacitance retention of an OMCN-150 is 96.1%, which indicates that the electrochemical performance of the supercapacitor is improved greatly, and represents novel research and significant advances in the field of electrode composite materials for supercapacitor. -- Graphical abstract: A series of high performance nickel compound/ordered mesoporous carbon composites were synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time. Display Omitted
Feng, Jicheng; Zhao, Jiachang; Tang, Bohejin; Liu, Ping [College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Xu, Jingli, E-mail: email@example.com [College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)
Task 6.7.3 - Interfacial Mass Transport Effects in Composite Materials
Advanced metal-matrix composites (MMCS) consisting of titanium-based alloys possess some unique mechanical, physical, and chemical characteristics that make them highly desirable for aircraft and gas turbine engines. Tailoring MMC properties is essential for advanced product design in materials processing. The main factors that affect materials processing and, further, the nature of a metal-ceramic interface, its structure, and morphological stability is liquid surface mass transport related to adhesional wetting physical effect) and reactive wetting (chemical effect). Surfaces and interfaces dominate many of the technologically important processes in composite materials such as liquid-solid sintering and joining. The objective of this work is threefold: 1) to get insight into the role of the nonstoichiometry of chemical composition in ceramic materials used as reinforcement components in MMC processing, 2) to extend previous energetic analysis of mass transport phenomena to wetting behavior between liquid metal and the quasi-solid like skin resulting from the presolidification of liquid on nonstoichiometric solids on a scale of interatomic distance, and 3) to provide experimental verification of our concept.
Jan W. Nowok
A methodology for the structural analysis of composite wind turbine blades under geometric and material induced instabilities
The objective of this work is to develop a modeling strategy for the structural analysis of large three-dimensional laminated composite structures undergoing geometric and material induced instability. A sub-modeling approach is used with multiple mixed-mode ... Keywords: Buckling, Composite materials, Damage mechanics, Delamination, Nonlinear finite element, Solution strategy
L. C. T. Overgaard; E. Lund; P. P. Camanho
Method and apparatus for the application of textile treatment compositions to textile materials
A system for applying textile treatment compositions to textile materials. A conduit member is provided which includes a passageway having a first end, a second end, and a medial portion with a constricted (narrowed) region. The passageway may include at least one baffle having an opening therethrough. A yarn strand is then moved through the passageway. A textile treatment composition (a sizing agent or dye) dissolved in a carrier medium (a supercritical fluid or liquified gas) is thereafter introduced into the constricted region, preferably at an acute angle relative to the passageway. The carrier medium expands inside the passageway which causes delivery of the treatment composition to the yarn. The treated yarn then passes through the baffle (if used) which facilitates drying of the yarn. During this process, a carrier gas can be introduced into the passageway to ensure the production of a smooth, dry product.
Argyle, Mark D. (Idaho Falls, ID); Propp, William Alan (Idaho Falls, ID)
A system is described for applying textile treatment compositions to textile materials. A conduit member is provided which includes a passageway having a first end, a second end, and a medial portion with a constricted (narrowed) region. The passageway may include at least one baffle having an opening there through. A yarn strand is then moved through the passageway. A textile treatment composition (a sizing agent or dye) dissolved in a carrier medium (a supercritical fluid or liquefied gas) is thereafter introduced into the constricted region, preferably at an acute angle relative to the passageway. The carrier medium expands inside the passageway which causes delivery of the treatment composition to the yarn. The treated yarn then passes through the baffle (if used) which facilitates drying of the yarn. During this process, a carrier gas can be introduced into the passageway to ensure the production of a smooth, dry product. 1 fig.
Argyle, M.D.; Propp, W.A.
Study of thermal properties of graphene-based structures using the force constant method
The thermal properties of graphene-based materials are theoretically investigated. The fourth-nearest neighbor force constant method for phonon properties is used in conjunction with both the Landauer ballistic and the non-equilibrium Green's function ... Keywords: Force constant method, Graphene, Graphene antidots, Non-equilibrium Green's function, Thermal properties
Hossein Karamitaheri; Neophytos Neophytou; Mahdi Pourfath; Hans Kosina
Deposition and FIB direct patterning of nanowires and nanorings into suspended sheets of graphene
Graphene, a one-atom-thick layer of carbon represents a new class of materials which offers new inroads into low-dimensional physics. Nowadays a crucial problem is related to the patterning of graphene structures while keeping intact the unusual physical ... Keywords: FIB Patterning, Quantum nanostructures, Suspended graphene
D. Lucot; J. Gierak; A. Ouerghi; E. Bourhis; G. Faini; D. Mailly
Composition and methods of preparation of target material for producing radionuclides
A composition suitable for use as a target containing antimony to be irradiated by accelerated charged particles (e.g., by protons to produce tin-117m) comprises an intermetallic compound of antimony and titanium which is synthesized at high-temperature, for example, in an arc furnace. The formed material is powdered and melted in an induction furnace, or heated at high gas pressure in gas static camera. The obtained product has a density, temperature stability, and heat conductivity sufficient to provide an appropriate target material.
Seropeghin, Yurii D; Zhuikov, Boris L
Crystallographic Etching of Few-Layer Graphene
We demonstrate a method by which few-layer graphene samples can be etched along crystallographic axes by thermally activated metallic nanoparticles. The technique results in long (>1 µm) crystallographic edges etched through to the insulating substrate, making the process potentially useful for atomically precise graphene device fabrication. This advance could enable atomically precise construction of integrated circuits from single graphene sheets with a wide range of technological applications. Due to its remarkable electronic properties, few layer graphene is emerging as a promising new material for use in a vast array of postsilicon nanoelectronic devices incorporating quantum size effects. 1,2 Of particular interest would be the construction of atomically precise graphene nanoribbons, in which charge carriers are confined in the lateral dimension whereby the electronic properties are controlled by the width and specific crystallographic orientation of the ribbon. 3?14 Such structures hold enormous promise as nanoscale devices similar to those recently developed using carbon nanotubes 2,11,15 with the added advantage that graphenes two-dimensionality lends itself to existing device architectures based on planar geometries. However, these structures have so far been impossible to achieve because of the rough noncrystalline edges of the graphene that result from current state-of-the-art nanolithography techniques. 2,16,17 These rough edges
Sujit S. Datta; Douglas R. Strachan; Samuel M. Khamis; A. T. Charlie Johnson
Low-Cost Composite Materials for Polymer Electrolyte Fuel Cell Bipolar Plates
Polymer electrolyte fuel cells (PEFCS) are under widespread development to produce electrical power for a variety of stationary and transportation applications. To date, the bipolar plate remains the most problematic and costly component of PEFC stacks (1). In addition to meeting cost constraints, bipolar plates must possess a host of other properties, the most important of which are listed in Table 1. The most commonly used material for single cell testing is machined graphite, which is expensive and costly to machine. The brittle nature of graphite also precludes the use of thin components for reducing stack size and weight, which is particularly important for transportation applications. Other stack designs consider the use of metal hardware such as stainless steel (2,3). But a number of disadvantages are associated with stainless steel, including high density, high cost of machining, and possible corrosion in the fuel cell environment. In light of these difficulties, much of the recent work on fuel cell bipolar plate materials has concentrated on graphite/polymer composites (4--8). Composite materials offer the potential advantages of lower cost, lower weight, and greater ease of manufacture than traditional graphite and metal plates. For instance, flow fields can be molded directly into these composites, thereby eliminating the costly and difficult machining step required for graphite or metal hardware.
Busick, D.N.; Wilson, M.S.
Evaluation of Composite Alumina Nanoparticle and Nitrate Eutectic Materials for use in Concentrating Solar Power Plants
The focus of this research was to create and characterize high temperature alumina and nitrate salt eutectic nanofluids for use in thermal energy storage (TES) systems. The nitrate eutectic was originally used in the TES system demonstrated as part of the Solar Two power tower and is currently employed as the TES material at Andasol 1 in Spain. Concentrations of alumina nanoparticles between 0.1% and 10% by weight were introduced into the base material in an effort to create nanofluids which would exhibit improved specific heat capacity to reduce the $/kWht thermal energy storage system costs. The composite materials were created using an aqueous mixing method in which both the nanoparticles and nitrate eutectic were placed into solution using acidic water. This solution was then sonicated in an ultrasonic bath in an effort to reduce nanoparticle agglomeration and to improve homogeneity. After boiling off the excess water, the nanoparticle-nitrate eutectic composite was recovered for characterization. The thermal properties of both the composite and base materials were characterized using the differential scanning calorimetry techniques outlined in ASTM E 1269. The created nanofluids were not stable and did not offer a cost-effective alternative to the current nitrate eutectic TES material. Despite these setbacks, a positive correlation between alumina concentration and nanofluid specific heat was demonstrated. Additionally, the specific heat capacities of the created nanofluids exceeded that predicted by the current theoretical models. These findings suggest that further work in the field of high temperature nanofluids for use in TES systems is warranted.
Malik, Darren R.
Sandwich-Type Functionalized Graphene Sheet-Sulfur Nanocomposite for Rechargeable Lithium Batteries
A sandwich structured graphene sheet-sulfur (GSS) nanocomposite was synthesized as the cathode material for lithium-sulfur batteries. The structure has a layer of graphene stacks and a layer of sulfur nanoparticles integrated into a three-dimensional architecture. This GSS nanoscale layered composite, making use of the efficient physical and electrical contact between sulfur and the large surface area, highly conductive graphene, provides a high loading of active materials of ~70 wt%, a high tape density of ~0.92 g?cm-3, and a high power with a reversible capacity of ~505 mAh?g-1 (~464 mAh?cm-3) at a current density of 1,680 mA?g-1 (1C). When coated with a thin layer of cation exchange Nafion film, the migration of dissolved polysulfide anions from the GSS nanocomposite was effectively alleviated, leading to a good cycling stability of 75% capacity retention over 100 cycles. This sandwich-structured composite conceptually provides a new strategy for designing electrodes in energy storage applications.
Cao, Yuliang; Li, Xiaolin; Aksay, Ilhan A.; Lemmon, John P.; Nie, Zimin; Yang, Zhenguo; Liu, Jun
Geometric and Electronic Structure of Closed Graphene Edges
We report theoretical and experimental results on single and multiple looped graphene sheets. Experimental images of stable closed-edge structures in few-layer graphene samples obtained by high-resolution transmission electron microscopy (HRTEM) are compared with first- principles density functional theory calculations. We demonstrate that the electronic structure of a graphene nanoribbon is not significantly perturbed upon closing. By contrast, a significant modulation of the electronic structure is observed for closed-edge graphene structures deposited on a planar graphene substrate. This effect is due to an enhanced reactivity of the looped (coalesced) edges observed experimentally. The coexistence of different degrees of curvature in the graphene sheet induced by folding indicates that these materials could be used for surface chemistry engineering.
Lopez-Benzanilla, Alejandro [Oak Ridge National Laboratory (ORNL); Campos-Delgado, Jessica [IPICyT; Sumpter, Bobby G [ORNL; Baptista, Daniel [National Institute of Metrology, Duque de Caxias, Brazil; Hayashi, Takuya [Institute of Carbon Science and Technology, Shinshu Unversity; Kim, Y A [Shinshu University; Muramatsu, H [Shinshu University; Endo, M [Shinshu University; Achete, Carlos [National Institute of Metrology, Duque de Caxias, Brazil; Terrones, M. [Universidad Carlos III, Madrid, Spain; Meunier, Vincent [ORNL
Graphene Frequency Multipliers
In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...
Wang, Han
Integration and Joining of Ceramic Matrix Composites
Ceramic Matrix Composites for Nuclear and Fusion Energy · Crack Propagation in SiC Bicrystals Containing Intergranular Graphene · Creep Behavior of a ...
1 1.2 Thermal transport atxv Introduction xii 1.1 Thermal conductivity and65 4.13 Thermal conductivity of graphene as a function of
Thermal Conductivity of Thermally-Isolating Polymeric and Composite Structural Support Materials Between 0.3 and 4 K
We present measurements of the low-temperature thermal conductivity of a number of polymeric and composite materials from 0.3 to 4 K. The materials measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301, G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and graphite rod. These materials have moderate to high elastic moduli making them useful for thermally-isolating structural supports.
Runyan, M C
M. C. Runyan; W. C. Jones
Investigation of Polymer Resin/Fiber Compatibility in Natural Fiber Reinforced Composite Automotive Materials
Natural fibers represent a lower density and potentially lower cost alternative to glass fibers for reinforcement of polymers in automotive composites. The high specific modulus and strength of bast fibers make them an attractive option to replace glass not only in non-structural automotive components, but also in semi-structural and structural components. Significant barriers to insertion of bast fibers in the fiber reinforced automotive composite market include the high moisture uptake of this lignocellulosic material relative to glass and the weak inherent interface between natural fibers and automotive resins. This work seeks to improve the moisture uptake and resin interfacing properties of natural fibers through improved fundamental understanding of fiber physiochemical architecture and development of tailored fiber surface modification strategies.
Fifield, Leonard S.; Huang, Cheng; Simmons, Kevin L.
Composit, Nanoparticle-Based Anode material for Li-ion Batteries Applied in Hybrid Electric (HEV's)
Lithium-ion batteries are promising energy storage devices in hybrid and electric vehicles with high specific energy values ({approx}150 Wh/kg), energy density ({approx}400 Wh/L), and long cycle life (>15 years). However, applications in hybrid and electric vehicles require increased energy density and improved low-temperature (<-10 C) performance. Silicon-based anodes are inexpensive, environmentally benign, and offer excellent theoretical capacity values ({approx}4000 mAh/g), leading to significantly less anode material and thus increasing the overall energy density value for the complete battery (>500 Wh/L). However, tremendous volume changes occur during cycling of pure silicon-based anodes. The expansion and contraction of these silicon particles causes them to fracture and lose electrical contact to the current collector ultimately severely limiting their cycle life. In Phase I of this project Yardney Technical Products, Inc. proposed development of a carbon/nano-silicon composite anode material with improved energy density and silicon's cycleability. In the carbon/nano-Si composite, silicon nanoparticles were embedded in a partially-graphitized carbonaceous matrix. The cycle life of anode material would be extended by decreasing the average particle size of active material (silicon) and by encapsulation of silicon nanoparticles in a ductile carbonaceous matrix. Decreasing the average particle size to a nano-region would also shorten Li-ion diffusion path and thus improve rate capability of the silicon-based anodes. Improved chemical inertness towards PC-based, low-temperature electrolytes was expected as an additional benefit of a thin, partially graphitized coating around the active electrode material.
Dr. Malgorzata Gulbinska
Influence of selected alkoxysilanes on dispersive properties and surface chemistry of titanium dioxide and TiO2-SiO2 composite material
The paper reports on characterisation of titanium dioxide and coprecipitated TiO2-SiO2 composite material functionalised with selected alkoxysilanes. Synthetic composite material was obtained by an emulsion method with cyclohexane ...
Katarzyna Siwi?ska-Stefa?ska, Filip Ciesielczyk, Magdalena Nowacka, Teofil Jesionowski
Type B plutonium transport package development that uses metallic filaments and composite materials
A new package was developed for transporting Pu and U quantities that are currently carried in DOT-6M packages. It uses double containment with threaded closures and elastomeric seals. A composite overpack of metallic wire mesh and ceramic or quartz cloth insulation is provided for protection in accidents. Two prototypes were subjected to dynamic crush tests. A thermal computer model was developed and benchmarked by test results to predict package behavior in fires. The material performed isotropically in a global fashion. A Type B Pu transport package can be developed for DOE Pu shipments for less than $5000 if manufactured in quantity. 5 figs, 6 refs. (DLC)
Pierce, J.D.; Moya, J.L.; McClure, J.D.; Hohnstreiter, G.F. (Sandia National Labs., Albuquerque, NM (United States)); Golliher, K.G. (USDOE Albuquerque Operations Office, NM (United States))
Method and apparatus for analyzing the internal chemistry and compositional variations of materials and devices
A method and apparatus is disclosed for obtaining and mapping chemical compositional data for solid devices. It includes a SIMS mass analyzer or similar system capable of being rastered over a surface of the solid to sample the material at a pattern of selected points, as the surface is being eroded away by sputtering or a similar process. The data for each point sampled in a volume of the solid is digitally processed and indexed by element or molecule type, exact spacial location within the volume, and the concentration levels of the detected element or molecule types. This data can then be recalled and displayed for any desired planar view in the volume.
Kazmerski, L.L.
A graphene electron lens
An epitaxial layer of graphene was grown on a pre patterned 6H-SiC(0001) crystal. The graphene smoothly covers the hexagonal nano-holes in the substrate without the introduction of small angle grain boundaries or dislocations. This is achieved by an elastic deformation of the graphene by {approx_equal}0.3% in accordance to its large elastic strain limit. This elastic stretching of the graphene leads to a modification of the band structure and to a local lowering of the electron group velocity of the graphene. We propose to use this effect to focus two-dimensional electrons in analogy to simple optical lenses.
Gerhard, L.; Balashov, T.; Wulfhekel, W. [Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131 Karlsruhe (Germany); Moyen, E.; Ozerov, I.; Sahaf, H.; Masson, L.; Hanbuecken, M. [CINaM-CNRS, Aix-Marseille University, Campus Luminy - Case 913, 18288 Marseille (France); Portail, M. [CRHEA-CNRS, Parc de Sophia - Antipolis, rue B. Gregory, 06560 Valbonne (France)
Use Of Superacids To Digest Chrysotile And Amosite Asbestos In Simple Mixtures Or Matrices Found In Building Materials Compositions
A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a flouro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP(O)(OH).sub.2, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided
Sugama, Toshifumi (Wading River, NY); Petrakis, Leon (Port Jefferson, NY); Webster, Ronald P. (Shoreham, NY)
Plasmonic graphene transparent conductors.
Plasmonic graphene is fabricated using thermally assisted self-assembly of silver nanoparticles on graphene. The localized surface-plasmonic effect is demonstrated with the resonance frequency shifting from 446 to 495 nm when the lateral dimension of the Ag nanoparticles increases from about 50 to 150 nm. Finite-difference time-domain simulations are employed to confirm the experimentally observed light-scattering enhancement in the solar spectrum in plasmonic graphene and the decrease of both the plasmonic resonance frequency and amplitude with increasing graphene thickness. In addition, plasmonic graphene shows much-improved electrical conductance by a factor of 2-4 as compared to the original graphene, making the plasmonic graphene a promising advanced transparent conductor with enhanced light scattering for thin-film optoelectronic devices.
Xu, G.; Liu, J.; Wang, Q.; Hui, R.; Chen, Z.; Maroni, V. A.; Wu, J. (Materials Science Division); (Univ. Kansas)
Substrate-Induced Band-Gap Opening in Epitaxial Graphene
Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Prospective challengers to silicon, the long-reigning king of semiconductors for computer chips and other electronic devices, have to overcome silicon's superb collection of materials properties as well as sophisticated fabrication technologies refined by six decades of effort by materials scientists and engineers. Graphene, one of the latest contenders, has a rather impressive list of features of its own but has lacked a key characteristic of all semiconductors, an energy gap (band gap) in its electronic band structure. A multi-institutional collaboration under the leadership of researchers with Berkeley Lab and the University of California, Berkeley, have now demonstrated that growing an epitaxial film of graphene on a silicon carbide substrate results in a significant band gap, 0.26 electron volts (eV), an important step toward making graphene useful as a semiconductor.
Materials Go/No-Go Recommendation Document
Ultimate targets. Several inexpensive material systems and synthetic pathways (e.g., Calcium Ca integrated with graphene and other 5 framework materials) have been...
Photoluminescence from Carbon-based Hybrid Materials
We shall like to present our results in incorporating optical nanoparticle materials, such as Er and ZnO into carbon-based materials, ranging from graphene to ...
Electron spin-flip scattering in graphene due to substrate impurities.
??Graphene has long been known for its peculiar Dirac-like band structure which lends it many of its remarkable properties. It is a promising material for… (more)
Goswami, Aditi
Nanostructured Cobalt Ferrites, Multifunctional Materials
... perspective of combining many functionalities in future generations of remote switchable ... Graphene-like 2D-layered Materials for Nanoelectronics & Sensing
Standard test method for translaminar fracture toughness of laminated and pultruded polymer matrix composite materials
1.1 This test method covers the determination of translaminar fracture toughness, KTL, for laminated and pultruded polymer matrix composite materials of various ply orientations using test results from monotonically loaded notched specimens. 1.2 This test method is applicable to room temperature laboratory air environments. 1.3 Composite materials that can be tested by this test method are not limited by thickness or by type of polymer matrix or fiber, provided that the specimen sizes and the test results meet the requirements of this test method. This test method was developed primarily from test results of various carbon fiber – epoxy matrix laminates and from additional results of glass fiber – epoxy matrix, glass fiber-polyester matrix pultrusions and carbon fiber – bismaleimide matrix laminates (1-4, 6, 7). 1.4 A range of eccentrically loaded, single-edge-notch tension, ESE(T), specimen sizes with proportional planar dimensions is provided, but planar size may be variable and adjusted, with asso...
American Society for Testing and Materials. Philadelphia
Pulsed, Photonuclear-induced, Neutron Measurements of Nuclear Materials with Composite Shielding
Active measurements were performed using a 10-MeV electron accelerator with inspection objects containing various nuclear and nonnuclear materials available at the Idaho National Laboratory's Zero Power Physics Reactor (ZPPR) facility. The inspection objects were assembled from ZPPR reactor plate materials to evaluate the measurement technologies for the characterization of plutonium, depleted uranium or highly enriched uranium shielded by both nuclear and non-nuclear materials. A series of pulsed photonuclear, time-correlated measurements were performed with unshielded calibration materials and then compared with the more complex composite shield configurations. The measurements used multiple 3He detectors that are designed to detect fission neutrons between pulses of an electron linear accelerator. The accelerator produced 10-MeV bremsstrahlung X-rays at a repetition rate of 125 Hz (8 ms between pulses) with a 4-us pulse width. All inspected objects were positioned on beam centerline and 100 cm from the X-ray source. The time-correlated data was collected in parallel using both a Los Alamos National Laboratory-designed list-mode acquisition system and a commercial multichannel scaler analyzer. A combination of different measurement configurations and data analysis methods enabled the identification of each object. This paper describes the experimental configuration, the ZPPR inspection objects used, and the various measurement and analysis results for each inspected object.
James Jones; Kevin Haskell; Rich Waston; William Geist; Jonathan Thron; Corey Freeman; Martyn Swinhoe; Seth McConchie; Eric Sword; Lee Montierth; John Zabriskie
Fatigue of Composite Material Beam Elements Representative of Wind Turbine Blade Substructure
The database and analysis methods used to predict wind turbine blade structural performance for stiffness, static strength, dynamic response,and fatigue lifetime are validated through the design, fabrication, and testing of substructural elements. We chose a test specimen representative of wind turbine blade primary substructure to represent the spar area of a typical wind turbine blade. We then designed an I-beam with flanges and web to represent blade structure, using materials typical of many U.S.-manufactured blades. Our study included the fabrication and fatigue testing of 52 beams and many coupons of beam material. Fatigue lifetimes were consistent with predictions based on the coupon database. The final beam specimen proved to be a very useful tool for validating strength and lifetime predictions for a variety of flange and web materials, and is serving as a test bed to ongoing studies of structural details and the interaction between manufacturing and structural performance. Th e beam test results provide a significant validation of the coupon database and the methodologies for predicting fatigue of composite material beam elements.
Mandell, J. F.; Samborsky, D. D.; Combs, D. W.; Scott, M. E.; Cairns, D. S. (Department of Chemical Engineering, Montana State University)
Standard practice for radiologic examination of flat panel composites and sandwich core materials used in aerospace applications
1.1 This practice is intended to be used as a supplement to Practices E 1742, E 1255, and E 2033. 1.2 This practice describes procedures for radiologic examination of flat panel composites and sandwich core materials made entirely or in part from fiber-reinforced polymer matrix composites. Radiologic examination is: a) radiographic (RT) with film, b) Computed Radiography (CR) with Imaging Plate, c) Digital Radiology (DR) with Digital Detector Array's (DDA), and d) Radioscopic (RTR) Real Time Radiology with a detection system such as an Image Intensifier. The composite materials under consideration typically contain continuous high modulus fibers (> 20 GPa), such as those listed in 1.4. 1.3 This practice describes established radiological examination methods that are currently used by industry that have demonstrated utility in quality assurance of flat panel composites and sandwich core materials during product process design and optimization, process control, after manufacture inspection, in service exami...
The BURNUP package of applied programs used for computing the isotopic composition of materials of an operating nuclear reactor
This paper described the procedure of implementation and the possibilities of the BURNUP program. The purpose of the program is to predict the change in the nuclear composition of the materials of which a reactor is made in the course of its run and compute the radiation characteristics of the materials after their irradiation.
Yudkevich, M. S., E-mail: firstname.lastname@example.com [National Research Centre Kurchatov Institute (Russian Federation)
Potential industrial applications for composite phase-change materials as thermal energy storage media
Considerable effort has been spent by the US Department of Energy and its contractors over the last few years to develop composite phase-change materials (CPCMs) for thermal energy storage (TES). This patented TES medium consists of a phase-change material (typically a salt or metal alloy) that is retained within the porous structure of a supporting material (typically a ceramic). The objectives of this study were to (1) introduce CPCMs to industries that may not otherwise be aware of them, (2) identify potentially attractive applications for CPCM in industry, (3) determine technical requirements that will affect the design of CPCM's for specific applications, and (4) generate interest among industrial firms for employing CPCM TES in their processes. The approach in this study was to examine a wide variety of industries using a series of screens to select those industries that would be most likely to adopt CPCM TES in their processes. The screens used in this study were process temperature, presence of time-varying energy flows, energy intensity of the industry, and economic growth prospects over the next 5 years. After identifying industries that passed all of the screens, representatives of each industry were interviewed by telephone to introduce them to CPCM TES, assess technical requirements for CPCM TES in their industry, and determine their interest in pursuing applications for CPCM TES. 11 refs., 4 tabs.
Spanner, G.E.; Wilfert, G.L.
Neutron Radiography and Fission Mapping Measurements of Nuclear Materials with Varying Composition and Shielding
Neutron radiography and fission mapping measurements were performed on four measurement objects with varying composition and shielding arrangements at the Idaho National Laboratory's Zero Power Physics Reactor (ZPPR) facility. The measurement objects were assembled with ZPPR reactor plate materials comprising plutonium, natural uranium, or highly enriched uranium and were presented as unknowns for characterization. As a part of the characterization, neutron radiography was performed using a deuterium-tritium (D-T) neutron generator as a source of time and directionally tagged 14 MeV neutrons. The neutrons were detected by plastic scintillators placed on the opposite side of the object, using the time-correlation-based data acquisition of the Nuclear Materials Identification System developed at Oak Ridge National Laboratory. Each object was measured at several rotations with respect to the neutron source to obtain a tomographic reconstruction of the object and a limited identification of materials via measurement of the neutron attenuation. Large area liquid scintillators with pulse shape discrimination were used to detect the induced fission neutrons. A fission site map reconstruction was produced by time correlating the induced fission neutrons with each tagged neutron from the D-T neutron generator. This paper describes the experimental configuration, the ZPPR measurement objects used, and the neutron imaging and fission mapping results.
Mullens, James Allen [ORNL; McConchie, Seth M [ORNL; Hausladen, Paul [ORNL; Mihalczo, John T [ORNL; Grogan, Brandon R [ORNL; Sword, Eric D [ORNL
On the isothermal geometry of corrugated graphene sheets
Variational geometries describing corrugated graphene sheets are proposed. The isothermal material properties of these sheets are described by a 2-dimensional Weyl space. The equation that couples the Weyl geometry with isothermal distributions of the temperature of graphene sheets, is formulated. This material space is observed in a 3-dimensional orthogonal configurational point space as regular surfaces which are endowed with a thermal state vector field fulfilling the isothermal thermal state equation. It enables to introduce a non-topological dimensionless thermal shape parameter of non-developable graphene sheets. The properties of the congruence of lines generated by the thermal state vector field are discussed.
Andrzej Trzesowski
Graphene as a manufactured product : a look forward
Graphene's unique electrical and mechanical properties have brought it into the spotlight in recent years. With the number of patents increasing rapidly every year, production of the material is becoming more and more ...
Frost, Stephen T
Electromechanical properties of freestanding graphene functionalized with tin oxide (SnO{sub 2}) nanoparticles
Freestanding graphene membranes were functionalized with SnO{sub 2} nanoparticles. A detailed procedure providing uniform coverage and chemical synthesis is presented. Elemental composition was determined using scanning electron microscopy combined with energy dispersive x-ray analysis. A technique called electrostatic-manipulation scanning tunneling microscopy was used to probe the electromechanical properties of functionalized freestanding graphene samples. We found ten times larger movement perpendicular to the plane compared to pristine freestanding graphene and propose a nanoparticle encapsulation model.
Dong, L. [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, Missouri 65897 (United States); Hansen, J. [Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, Missouri 65897 (United States); Xu, P.; Ackerman, M. L.; Barber, S. D.; Schoelz, J. K.; Qi, D.; Thibado, P. M. [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
Transport Properties of Bilayer Graphene Nanoribbons
operation in single-layer graphene ferroelectric memory".Mobility in Suspended Graphene. Solid State Commun. 2008,Transport in Suspended Graphene. Phys. Rev. Lett. 2008,
Wang, Minsheng
Local Density of States in Graphene
Continuum Hamiltonian for the graphene in the presence of afingerprints for adatoms in graphene: scanning tunnelingxi 4.10 Graphene LDOS at the adatom site (top carbon case)
Yang, Ling
Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash
Cementitious compositions useful as lightweight aggregates are formed from a blend of spent bed material from fluidized bed combustion and fly ash. The proportions of the blend are chosen so that ensuing reactions eliminate undesirable constituents. The blend is then mixed with water and formed into a shaped article. The shaped article is preferably either a pellet or a "brick" shape that is later crushed. The shaped articles are cured at ambient temperature while saturated with water. It has been found that if used sufficiently, the resulting aggregate will exhibit minimal dimensional change over time. The aggregate can be certified by also forming standardized test shapes, e.g., cylinders while forming the shaped articles and measuring the properties of the test shapes using standardized techniques including X-ray diffraction.
Boyle, Michael J. (Aston, PA)
Fluid flow modeling of resin transfer molding for composite material wind turbine blade structures.
Resin transfer molding (RTM) is a closed mold process for making composite materials. It has the potential to produce parts more cost effectively than hand lay-up or other methods. However, fluid flow tends to be unpredictable and parts the size of a wind turbine blade are difficult to engineer without some predictive method for resin flow. There were five goals of this study. The first was to determine permeabilities for three fabrics commonly used for RTM over a useful range of fiber volume fractions. Next, relations to estimate permeabilities in mixed fabric lay-ups were evaluated. Flow in blade substructures was analyzed and compared to predictions. Flow in a full-scale blade was predicted and substructure results were used to validate the accuracy of a full-scale blade prediction.
Cairns, Douglas S. (Montana State University, Bozeman, MT); Rossel, Scott M. (Montana State University, Bozeman, MT)
The Study of Composite Material Package for Optical Transceiver Module with High Shielding Effectiveness.
??We investigate the EM properties of four different type composites which are nylon and liquid-crystal polymer with carbon fiber filler composites, woven continuous carbon fiber… (more)
Lin, Cheng-Wei
Electrostatic Graphene Loudspeaker
Alex Zettl and Qin Zhou of Berkeley Lab have developed a miniaturized graphene-based electrostatic audio transducer. The speaker / earphone is ...
Writable graphene: Breaking sp2 bonds with soft X-rays
We study the stability of various kinds of graphene samples under soft x-ray irradiation. Our results show that in single-layer exfoliated graphene (a closer analog to two-dimensional material), the in-plane carbon-carbon bonds are unstable under x-ray irradiation, resulting in nanocrystalline structures. As the interaction along the third dimension increases by increasing the number of graphene layers or through the interaction with the substrate (epitaxial graphene), the effect of x-ray irradiation decreases and eventually becomes negligible for graphite and epitaxial graphene. Our results demonstrate the importance of the interaction along the third dimension in stabilizing the long range in-plane carbon-carbon bonding, and suggest the possibility of using x-ray to pattern graphene nanostructures in exfoliated graphene.
Zhou, S.; Girit, C.; Scholl, A.; Jozwiak, C.; Siegel, D.; Yu, P.; Robinson, J.; Wang, F.; Zettl, A.; Lanzara, A.
Graphene Monolayer Rotation on Ni(111) Facilities Bilayer Graphene Growth
Synthesis of bilayer graphene by chemical vapor deposition is of importance for graphene-based field effect devices. Here, we demonstrate that bilayer graphene preferentially grows by carbon-segregation under graphene sheets that are rotated relative to a Ni(111) substrate. Rotated graphene monolayer films can be synthesized at growth temperatures above 650 C on a Ni(111) thin-film. The segregated second graphene layer is in registry with the Ni(111) substrate and this suppresses further C-segregation, effectively self-limiting graphene formation to two layers.
Batzill M.; Sutter P.; Dahal, A.; Addou, R.
Composition-tailored synthesis of gradient transition metal precursor particles for lithium-ion battery cathode materials.
We report the tailored synthesis of particles with internal gradients in transition metal composition aided by the use of a general process model. Tailored synthesis of transition metal particles was achieved using a coprecipitation reaction with tunable control over the process conditions. Gradients in the internal composition of the particles was monitored and confirmed experimentally by analysis of particles collected during regularly timed intervals. Particles collected from the reactor at the end of the process were used as the precursor material for the solid-state synthesis of Li{sub 1.2}(Mn{sub 0.62}Ni{sub 0.38}){sub 0.8}O{sub 2}, which was electrochemically evaluated as the active cathode material in a lithium battery. The Li{sub 1.2}(Mn{sub 0.62}Ni{sub 0.38}){sub 0.8}O{sub 2} material was the first example of a structurally integrated multiphase material with a tailored internal gradient in relative transition metal composition as the active cathode material in a lithium-ion battery. We believe our general synthesis strategy may be applied to produce a variety of new cathode materials with tunable interior, surface, and overall relative transition metal compositions.
Koenig, G. M.; Belharouak, I.; Deng, H.; Amine, K.; Sun, Y. K. (Chemical Sciences and Engineering Division)
Mechanical and electrochemical performance of composite cathode contact materials for solid oxide fuel cells
The feasibility of adding glass or inorganic binder to conventional SOFC cathode contact materials (CCM) in order to improve bonding to adjacent materials in the cell stack is assessed. Two glasses (SEM-COM SCZ-8 and Schott GM31107) and one inorganic binder (Aremco 644A) are mixed with LSM particles to produce composite CCM pastes. These are used to bond Mn1.5Co1.5O4-coated stainless steel mesh current collectors to anode-supported button cells. The cells are operated at 800 C for about 1000 h. The cell with SCZ-8 addition to the CCM displays quite stable operation (3.9%/1000 h degradation), whereas the other additives lead to somewhat higher degradation rate. Bonding of the CCM to coated stainless steel coupons is also assessed. Interfacial fracture toughness is determined using a four-point bend test. The fracture toughness for LSM Schott glass (12.3 N mm 1), LSM SCZ-8 glass (6.8 N mm 1) and LSM 644A binder (5.4 N mm 1) are significantly improved relative to pure LSM (1.7 N mm 1). Indeed, addition of binder or glass is found to improve bonding of the CCM layer without sacrificing cell performance.
Tucker, Michael C. [Lawrence Berkeley National Laboratory (LBNL); Dejonghe, Lutgard C. [Lawrence Berkeley National Laboratory (LBNL); Garcia-Negron, Valerie [Material Science and Technology Division, Oak Ridge National Laboratory; Trejo, Rosa M [ORNL; Lara-Curzio, Edgar [ORNL
"Developing Hybrid Polymer Composites with Embedded Shape-Memory Alloy Wires" (Overview), P. Sittner and R. Stalmans, October 2000, pp. 15-20.
Revisit Carbon/Sulfur Composite for Li-S Batteries
To correlate the carbon properties e.g. surface area and porous structure, with the electrochemical behaviors of carbon/sulfur (C/S) composite cathodes for lithium-sulfur (Li-S) batteries, four different carbon frameworks including Ketjen Black (KB, high surface area and porous), Graphene (high surface area and nonporous), Acetylene Black (AB, low surface area and nonporous) and Hollow Carbon Nano Sphere (HCNS, low surface area and porous) are employed to immobilize sulfur (80 wt.%). It has been revealed that high surface area of carbon improves the utilization rate of active sulfur and decreases the real current density during the electrochemical reactions. Accordingly, increased reversible capacities and reduced polarization are observed for high surface area carbon hosts such as KB/S and graphene/S composites. The porous structure of KB or HCNS matrix promotes the long-term cycling stability of C/S composites but only at relatively low rate (0.2 C). Once the current density increases, the pore effect completely disappears and all Li-S batteries show similar trend of capacity degradation regardless of the different carbon hosts used in the cathodes. The reason has been assigned to the formation of reduced amount of irreversible Li2S on the cathode as well as shortened time for polysulfides to transport towards lithium anode at elevated current densities. This work provides valuable information for predictive selection on carbon materials to construct C/S composite for practical applications from the electrochemical point of view.
Zheng, Jianming; Gu, Meng; Wagner, Michael J.; Hays, Kevin; Li, Xiaohong S.; Zuo, Pengjian; Wang, Chong M.; Zhang, Jiguang; Liu, Jun; Xiao, Jie
Emergent gravity in graphene
We reconsider monolayer graphene in the presence of elastic deformations. It is described by the tight - binding model with varying hopping parameters. We demonstrate, that the fermionic quasiparticles propagate in the emergent 2D Weitzenbock geometry and in the presence of the emergent U(1) gauge field. Both emergent geometry and the gauge field are defined by the elastic deformation of graphene.
M. A. Zubkov; G. E. Volovik
Organometallic Complexes of Graphene
We demonstrate the organometallic hexahapto complexation of chromium with graphene, graphite and carbon nanotubes. All of these extended periodic pi-electron systems exhibit some degree of reactivity toward the reagents CrCO)6 and (eta6-benzene)Cr(CO)3, and we are able to demonstrate the formation of (eta6-rene)Cr(CO)3 or (eta6-arene)2Cr, where arene = single-walled carbon nanotubes (SWNT), exfoliated graphene (XG), epitaxial graphene (EG) and highly-oriented pyrolytic graphite (HOPG). We find that the SWNTs are the least reactive presumably as a result of the effect of curvature on the formation of the hexahapto bond; in the case of HOPG, (eta6-HOPG)Cr(CO)3 was isolated while the exfoliated graphene samples were found to give both (eta6-graphene)2Cr, and (eta6-graphene)Cr(CO)3 structures. We report simple and efficient routes for the mild decomplexation of the graphene-chromium complexes which appears to restore the original pristine graphene state. This study represents the first example of the use of graph...
Sarkar, Santanu; Bekyarova, Elena; Haddon, Robert C
Zubkov, M A
Graphene Terahertz Plasmon Oscillators
In this paper we propose and discuss coherent terahertz sources based on charge density wave (plasmon) amplification in two-dimensional graphene. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers ... Keywords: Carbon, Nanotechnology, Plasmons, Submillimeter Wave Oscillators, nanotechnology, plasmons, submillimeter-wave oscillators
F. Rana
Probing Graphene Electronic Devices with Atomic Scale ...
... News Articles: Real-World Graphene Devices May Have a Bumpy Ride. Two Graphene Layers May Be Better Than One. ...
Quantum Conductance Project/Graphene-Based Quantum ...
Quantum Conductance Project/Graphene-Based Quantum Metrology. Summary: ... Graphene Hall bar developed at NIST by undergraduate students. ...
A Virtual Test Approach to Incorporate Materials and Manufacturing Processes to Aid Design choices in High Performance Composites
The increasing use of fibre reinforced composites in structural components in the aerospace industry is providing many challenges to designers in understanding how they can be used more effectively to exploit their advantages. One of the main challenges is the selection of lay-ups for a given application. The difficulty lies in the variability that is achievable with composites. Each new layup or configuration is effectively a new material and requires and extensive test programme to validate the performance, from coupons which give basic material characteristics, up through the test pyramid through to large sub-component which contains basic assemblies. This variety of testing gives confidence in understanding the material behaviour and performance in structural assemblies. On the other hand, the manufacturing process is also important here with different processes sometimes needed for different materials or thicknesses. This is a time consuming and expensive process requiring many thousands of small tests leading up to a few major tests which are complex to set up and carry out. This research is attempting to address this by developing a virtual test system which will sit hand-in-hand with a physical test system. The goal of virtual tests appears reachable using the finite element analysis technique in which many experimental tests can be replaced by high fidelity simulations. The payoff in reduced cycle time and costs for designing and certifying composite structures is very attractive; and the possibility also arises of considering material configurations that are too complex to certify by purely empirical methods. The validated simulations could then be subsequently used for variants or derivatives of composites to inform design choices and establish new validation programmes where appropriate. This paper presents a series of simulations of the critical testing procedures needed to validate high performance composites materials using linear and non-linear models and compares the results with physical test performed in carbon fibre specimens.
Gonzalez-Murillo, C.; Price, M. [School of Mechanical and Aerospace Engineering, Queens University, Belfast (United Kingdom)
Imaging Stacking Order in Few-Layer Graphene
Few-layer graphene (FLG) has been predicted to exist in various crystallographic stacking sequences, which can strongly influence the material's electronic properties. We demonstrate an accurate and efficient method to characterize stacking order in FLG using the distinctive features of the Raman 2D-mode. Raman imaging allows us to visualize directly the spatial distribution of Bernal (ABA) and rhombohedral (ABC) stacking in tri- and tetralayer graphene. We find that 15% of exfoliated graphene tri- and tetralayers is composed of micrometer-sized domains of rhombohedral stacking, rather than of usual Bernal stacking. These domains are stable and remain unchanged for temperatures exceeding 800 C.
C Lui; Z Li; Z Chen; P Klimov; L Brus; T Heinz
Argonne CNM News: STM of individual grains in CVD-grown graphene
STM of individual grains in CVD-grown graphene STM of individual grains in CVD-grown graphene SEM of 3d supercrystals The first scanning tunneling microscopy (STM) images of graphene synthesized on copper foil. (b-d) show atomic-resolution images at various locations of the large graphene domain shown in (a). NMAT June 2011 Users from Purdue University, working collaboratively with staff in the Electronic & Magnetic Materials & Devices Group, studied CVD-grown graphene on polycrystalline copper foil for the first time at the atomic-scale. The ultrahigh vacuum scanning tunneling microscopy (UHV-STM) findings performed at the Center for Nanoscale Materials (CNM) will help to guide the optimization of synthesis towards defect-free graphene. The focus of this study was to investigate the quality of the films and
Stabilization of Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene Triple Junction Points
Carbon-supported metal catalysts are widely used in heterogeneous catalysis and electrocatalysis. In this paper, we report a novel method to deposit metal catalysts and metal oxide nanoparticles on two-dimensional graphene sheets to improve the catalytic performance and stability of the catalyst materials. The new synthesis method allows indium tin oxide (ITO) nanocrystals to be directly grown on functionalized graphene sheets forming the ITO-graphene hybrids. Pt nanoparticles are then deposited to form a special triple-junction structure (Pt-ITO-graphene). Both experimental study and periodic density functional theory calculations show that the supported Pt nanoparticles are stable at Pt-ITO-graphene triple junction points. The new catalyst materials were tested for oxygen reduction for potential applications in polymer electrolyte membrane fuel cells, and they exhibited greatly enhanced stability and activity. The reasons for the high stability and activity of Pt-ITO-graphene are analyzed.
Kou, Rong; Shao, Yuyan; Mei, Donghai; Nie, Zimin; Wang, Donghai; Wang, Chong M.; Viswanathan, Vilayanur V.; Park, Seh K.; Aksay, Ilhan A.; Lin, Yuehe; Wang, Yong; Liu, Jun
Final Scientific Report, New Proton Conductive Composite Materials for PEM Fuel Cells
This project covered one of the main challenges in present-day PEM fuel cell technology: to design a membrane capable of maintaining high conductivity and mechanical integrity when temperature is elevated and water vapor pressure is severely reduced. The DOE conductivity milestone of 0.1 S cm-1 at 120 degrees C and 50 % relative humidity (RH) for designed membranes addressed the target for the project. Our approach presumed to develop a composite membrane with hydrophilic proton-conductive inorganic material and the proton conductive polymeric matrix that is able to "bridge" the conduction paths in the membrane. The unique aspect of our approach was the use of highly functionalized inorganic additives to benefit from their water retention properties and high conductivity as well. A promising result turns out that highly hydrophilic phosphorsilicate gels added in Nafion matrix improved PEM fuel cell performance by over 50% compared with bare Nafion membrane at 120 degrees C and 50 % RH. This achievement realizes that the fuel cell operating pressure can be kept low, which would make the PEM fuel cell much more cost efficient and adaptable to practical operating conditions and facilitate its faster commercialization particularly in automotive and stationary applications.
Lvov, Serguei
Efficient Heat Storage Materials: Metallic Composites Phase-Change Materials for High-Temperature Thermal Energy Storage
HEATS Project: MIT is developing efficient heat storage materials for use in solar and nuclear power plants. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun's not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. MIT is designing nanostructured heat storage materials that can store a large amount of heat per unit mass and volume. To do this, MIT is using phase change materials, which absorb a large amount of latent heat to melt from solid to liquid. MIT's heat storage materials are designed to melt at high temperatures and conduct heat well—this makes them efficient at storing and releasing heat and enhances the overall efficiency of the thermal storage and energy-generation process. MIT's low-cost heat storage materials also have a long life cycle, which further enhances their efficiency.
Plasmons in Waveguide Structures Formed by Two Graphene Layers
Plasmon modes in a waveguide formed by two parallel graphene layers with an insulator spacer layer are considered. The existence of TM and TE guided modes is predicted and their properties are compared with those of plasmons in metal/insulator waveguides. DOI: 10.1134/S0021364013090063 Much attention has been attracted in recent years to graphene, a material made up of a two-dimensional lattice of carbon atoms [1–4]. From the fundamental point of view, graphene is interesting because charge carriers in this material are characterized by a linear dispersion relation, which leads to such phenomena as the room-temperature quantum Hall effect [5] and the existence of a nonzero Berry phase for charge carriers [2]. Graphene is also promising for applications owing to the high charge-carrier mobility, which is required for the new generation of electronic integrated circuits [6].
unknown authors
Ternary Self-Assembly of Ordered Metal Oxide Graphene Nanocomposites for
nanocrystal- line SnO2 with a 4- to 5-nm diameter interspaced by graphene stacks. (E) High-resolution TEM, the electrode (SnO2 or graphene materials) is charged to a high voltage (e.g., 0 3 V).38,61 The higher voltage and the (0002) plane in graphene stacks are shown in the high- resolution TEM image (Figure 2E). It should
Aksay, Ilhan A.
Graphene and Graphene Oxide: Biofunctionalization and Applications in Biotechnology
Graphene is the basic building block of zero-dimensional fullerene, 1D carbon nanotubes, and 3D graphite. Graphene has a unique planar structure as well as novel electronic properties, which have attracted great interest from scientists. This review selectively analyzes current advances in the field of graphene bioapplications. In particular, the functionalization of graphene for biological applications, FRET-based biosensor development by using graphene-based nanomaterials, and the investigation of graphene for living cell studies have been summarized in more details. Future perspectives and possible challenges in this rapidly developing area are also discussed.
Wang, Ying; Li, Zhaohui; Wang, Jun; Li, Jinghong; Lin, Yuehe
Forward model calculations for determining isotopic compositions of materials used in a radiological dispersal device
In the event that a radiological dispersal device (RDD) is detonated in the U.S. or near U.S. interests overseas, it will be crucial that the actors involved in the event can be identified quickly. If irradiated nuclear fuel is used as the dispersion material for the RDD, it will be beneficial for law enforcement officials to quickly identify where the irradiated nuclear fuel originated. One signature which may lead to the identification of the spent fuel origin is the isotopic composition of the RDD debris. The objective of this research was to benchmark a forward model methodology for predicting isotopic composition of spent nuclear fuel used in an RDD while at the same time optimizing the fidelity of the model to reduce computational time. The code used in this study was Monteburns-2.0. Monteburns is a Monte Carlo based neutronic code utilizing both MCNP and ORIGEN. The size of the burnup step used in Monteburns was tested and found to converge at a value of 3,000 MWd/MTU per step. To ensure a conservative answer, 2,500 MWd/MTU per step was used for the benchmarking process. The model fidelity ranged from the following: 2-dimensional pin cell, multiple radial-region pin cell, modified pin cell, 2D assembly, and 3D assembly. The results showed that while the multi-region pin cell gave the highest level of accuracy, the difference in uncertainty between it and the 2D pin cell (0.07% for 235U) did not warrant the additional computational time required. The computational time for the multiple radial-region pin cell was 7 times that of the 2D pin cell. For this reason, the 2D pin cell was used to benchmark the isotopics with data from other reactors. The reactors from which the methodology was benchmarked were Calvert Cliffs Unit #1, Takahama Unit #3, and Trino Vercelles. Calvert Cliffs is a pressurized water reactor (PWR) using Combustion Engineering 14??14 assemblies. Takahama is a PWR using Mitsubishi Heavy Industries 17??17 assemblies. Trino Vercelles is a PWR using non-standard lattice assemblies. The measured isotopic concentrations from all three of the reactors showed good agreement with the calculated values.
Burk, David Edward
Controlling Graphene's Electronic Structure Print Controlling Graphene's Electronic Structure Print Graphene, because of its unusual electron properties, reduced dimensionality, and scale, has enormous potential for use in ultrafast electronic transistors. It exhibits high conductivity and an anomalous quantum Hall effect (a phenomenon exhibited by certain semiconductor devices at low temperatures and high magnetic fields). Among its novel properties, graphene's electrical charge carriers (electrons and holes) move through a solid with effectively zero mass and constant velocity, like photons. Graphene's intrinsically low scattering rate from defects implies the possibility of a new kind of electronics based on the manipulation of electrons as waves rather than particles. The primary technical difficulty has been controlling the transport of electrical charge carriers through the sheet. This area of research is known as bandgap engineering. While bandgap engineering is the basis of semiconductor technology, it is only now being applied to graphene. Using angle-resolved photoemission spectroscopy (ARPES) at ALS Beamline 7.0.1, a team of scientists from the ALS and Germany characterized the electronic band structure and successfully controlled the gap between valence and conduction bands in a bilayer of graphene thin films deposited on a substrate of silicon carbide. This was done by doping one sheet with adsorbed potassium atoms, creating an asymmetry between the two layers.
Advanced Materials
Advanced Materials Advanced Materials Availability Technology Express Licensing Active Terahertz Metamaterial Devices Express Licensing Anion-Conducting Polymer, Composition, And...
Electrochemically Induced High Capacity Displacement Reaction of PEO/MoS2/Graphene Nanocomposites with Lithium
MoS2/PEO/graphene composite is successfully prepared and the discharge mechanism of MoS2 as an anode material for Li-ion batteries has been investigated systematically in this work. The simultaneous formation of Li2S and Mo at deep discharge depth has been shown for the first time. The deposition of Mo metal with Li residing on the defects after the first discharge increases the intrinsic electronic conductivity of the electrode leading to a superior cycling stability for over 185 cycles. After the first discharge the amorphous Mo matrix allows a large amount of Li+ ions to repeatedly deposit and being oxidized during cycling while the transition between Li2S and S contribute to the capacity above 2.0 V. The interactions between as-formed Mo and S prevents the dissolution of the intermediate polysulfide thus providing clues to immobilize the soluble species in a Li-S battery. Excellent rate performances are achieved in this MoS2/PEO/graphene composite indicating a fast diffusion path of Li+ ions existing not only in the bulk material but also in the interface between the electrode and the electrolyte.
Xiao, Jie; Wang, Xaojian; Yang, Xiao-Qing; Xun, Shidi; Liu, Gao; Koech, Phillip K.; Liu, Jun; Lemmon, John P.
Shielding vacuum fluctuations with graphene
The Casimir-Polder interaction of ground-state and excited atoms with graphene is investigated with the aim to establish whether graphene systems can be used as a shield for vacuum fluctuations of an underlying substrate. We calculate the zero-temperature Casimir-Polder potential from the reflection coefficients of graphene within the framework of the Dirac model. For both doped and undoped graphene we show limits at which graphene could be used effectively as a shield. Additional results are given for AB-stacked bilayer graphene.
Sofia Ribeiro; Stefan Scheel
Ribeiro, Sofia
Structure-Processing-Property Relationships at the Fiber-Matrix Interface in Electron-Beam Cured Composite Materials
The objective of this project was to characterize the properties of the resin and the fiber- resin interface in electron beam cured materials by evaluating several structural and processing parameters. The Oak Ridge National Laboratory (ORNL) has recently determined that the interlaminar shear strength properties of electron beam cured composites were 19-28% lower than for autoclave cured composites. Low interlaminar shear strength is widely acknowledged as the key barrier to the successfid acceptance and implementation of electron beam cured composites in industry. In this project we found that simple resin modification and process improvements are unlikely to substantially improve the interlaminar shear strength properties of electron beam cured composites. However, sizings and coatings were shown to improve these properties and there appears to be significant potential for further improvement. In this work we determined that the application of epoxy-based, electron beam compatible sizings or coatings onto surface- treated, unsized carbon fibers improved the composite interlaminar shear strength by as much as 55% compared to composites fabricated from surface-treated, unsized carbon fibers and 11 YO compared to composites made from surface-treated, GP sized carbon fibers. This work has identified many promising pathways for increasing the interlaminar shear strength of electron beam cured composites. As a result of these promising developments we have recently submitted a U.S. Department of Energy-Energy Research (DOE-ER) sponsored Laboratory Technical Research-Cooperative Research and Development Agreement (LTR- CRADA) proposal entitled, "Interracial Properties of Electron Beam Cured Composites", to continue this work. If funded, ORNL will lead a 3-year, $2.6 million effort involving eight industrial partners, NASA-Langley, and the U.S. Air Force. The principal objective of this CRADA is to significantly improve the interracial properties of carbon-fiber-reinforced composites beyond the current state-of-the art electron beam cured composites for use in several DOE, DoD, and industrial applications. In addition, several papers from this Laboratory Director's Research and Development (LDRD) project will be submitted to the Society for the Advancement of Materials and Process Engineering for oral presentations and publications.
Janke, C.J.
Polyethylene composites containing a phase change material having a C14 straight chain hydrocarbon
A composite useful in thermal energy storage, said composite being formed of a polyethylene matrix having a straight chain alkyl hydrocarbon incorporated therein, said polyethylene being crosslinked to such a degree that said polyethylene matrix is form stable and said polyethylene matrix is capable of absorbing at least 10% by weight of said straight chain alkyl hydrocarbon; the composite is useful in forming pellets or sheets having thermal energy storage characteristics.
Development of a liner-less composite CNG cylinder and improved mechanical properties of cylinder materials.
??xv, 91 leaves : ill. (some col.) ; 30 cm HKUST Call Number: Thesis MECH 2008 Iqbal Composite high pressure vessels are required in many… (more)
Iqbal, Kosar
(BaZrO 3 -ZnO)-BaTiO 3 Composite Materials
Mechanical Performance of Discontinuous Carbon Fiber-SiC Matrix Composites for Wear Components of High-Speed Train Applications · Multiscale Approach ...
Vorbeck Materials Corp. | Department of Energy
Vorbeck Vorbeck Materials Corp. America's Next Top Energy Innovator Challenge 45458 likes Vorbeck Materials Corp. Pacific Northwest National Laboratory Vorbeck Materials was founded in 2006 to bring to market products using graphene, a sheet of carbon that is only a single atom thick. Graphene is the strongest material ever tested and is electrically and thermally conductive. In recent years, there has been significant interest and activity on graphene research and its potential applications. The Aksay Labs at Princeton University produced a patented method for manufacturing graphene at commercial scale. Vorbeck signed a worldwide license for the Princeton technology and commissioned a ton-scale graphene manufacturing plant in 2007. The partnership between Vorbeck, PNNL and Princeton ultilizes graphene's
Graphene on Ru(0001): Evidence for two graphene band structures
High-resolution photoemission illustrates that the band structure of graphene on Ru(0001) exhibits a well-defined splitting. This splitting is largest with the graphene directly on the Ru(0001) substrate, whereas with a chemisorbed oxygen spacer layer between the graphene and the metal substrate, this splitting is considerably reduced. This splitting is attributed to a combination of chemical interactions between graphene and Ru(0001) and to screening of the former by the latter, not spin-orbit coupling.
Katsiev K.; Vescovo E.; Losovyj, Y.; Zhou, Z.; Liu, L.; Dowben, P.A.; Goodman, D.W.
Katsiev, Khabibulakh; Losovyj, Yaroslav; Zhou, Zihao; Vescovo, E; Liu, L.; Dowben, P. A.; Goodman, D. Wayne
CNST Graphene Publications
... edges of graphene devices, J. Chae, S. Jung, S. Woo, H. Baek, J. Ha, YJ Song, Y.-W. Son, NB Zhitenev, JA Stroscio, and Y. Kuk, Nano Letters 12 ...
Levitated Spinning Graphene
A method is described for levitating micron-sized few layer graphene flakes in a quadrupole ion trap. Starting from a liquid suspension containing graphene, charged flakes are injected into the trap using the electrospray ionization technique and are probed optically. At micro-torr pressures, torques from circularly polarized light cause the levitated particles to rotate at frequencies >1 MHz, which can be inferred from modulation of light scattering off the rotating flake when an electric field resonant with the rotation rate is applied. Possible applications of these techniques will be presented, both to fundamental measurements of the mechanical and electronic properties of graphene and to new approaches to graphene crystal growth, modification and manipulation.
B. E. Kane
Uncertainties in Gapped Graphene
Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.
Eylee Jung; Kwang S. Kim; DaeKil Park
Size quantization in planar graphene-based heterostructures: Pseudospin splitting, interface states, and excitons
A planar quantum-well device made of a gapless graphene nanoribbon with edges in contact with gapped graphene sheets is examined. The size-quantization spectrum of charge carriers in an asymmetric quantum well is shown to exhibit a pseudospin splitting. Interface states of a new type arise from the crossing of dispersion curves of gapless and gapped graphene materials. The exciton spectrum is calculated for a planar graphene quantum well. The effect of an external electric field on the exciton spectrum is analyzed.
Ratnikov, P. V., E-mail: email@example.com; Silin, A. P. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
Atomic layer etching of graphene for full graphene device fabrication
)/Ti(10 nm) and graphene is as high as 450Â800 O lm and this can degrade the character- istics graphene surface, while carbon with sp2 bonding under the CÂO bonding remains unetched, due to the high line is the transmittance of the bilayer graphene (before ALET). Other transmittance spectra were
Yeom, Geun Young
Annual Report Center for Nanophysics and Advanced Materials
in uncovering the unique electronic properties of graphene, which is a remarkable new material consisting. "Flexible Electronics, NanoCenter Industrial Workshop (Samsung)," August, 2007. "Graphene is all surface Function, Screening, and Plasmons in Two-Dimensional Graphene, E.H. Hwang and S. Das Sarma, Phys. Rev. B 75
Lathrop, Daniel P.
Use of Composite Pipe Materials in the Transportation of Natural Gas (INEEL/EXT-02-00992)
992 992 Use of Composite Pipe Materials in the Transportation of Natural Gas Patrick Laney July 2002 Idaho National Engineering and Environmental Laboratory Bechtel BWXT Idaho, LLC INEEL/EXT-02-00992 Use of Composite Pipe Materials in the Transportation of Natural Gas Sponsored by Natural Gas Pipeline Infrastructure Reliability Program National Energy Technology Laboratory INEEL Field Work Proposal # 4340-70 Prepared by: Patrick Laney Idaho National Engineering and Environmental Laboratory Idaho Falls, Idaho With Contributions From: Ian Kopp Kenway Corporation Augusta, Maine July 2002 Idaho National Engineering and Environmental Laboratory Fossil Energy Technologies Department Idaho Falls, Idaho 83415 Prepared for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy
Epitaxial Graphene - Energy Innovation Portal
Graphene has very interesting properties due to its electronic structure. For example, its thermal and electrical conductivities are extremely high ...
Review of composite material applications in the automotive industry for the electric and hybrid vehicle. Annual report, November 1978
A comprehensive review is made of the state-of-the-art in regard to the use of composite materials for reducing the structural mass of automobiles. Reduction of mass will provide, in addition to other engineering improvements, increased performance/range advantages that are particularly needed in the electric and hybrid vehicle field. Problems to be overcome include the attainment of mass production techniques and the prevention of environmental hazards.
Bauer, J.L.
scheme, known as the building block approach in MIL HDBK 17 [8], while figure 4 is a specific set, wind turbine blades, etc. Current Scale Up Approach For Composites Figure 3. MIL HDBK 17 Building Block
Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors
Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films. KEYWORDS: Graphene, flexible film, chemical activation, supercapacitors Free-standing thin film materials
Lithium ion batteries with titania/graphene anodes
Lithium ion batteries having an anode comprising at least one graphene layer in electrical communication with titania to form a nanocomposite material, a cathode comprising a lithium olivine structure, and an electrolyte. The graphene layer has a carbon to oxygen ratio of between 15 to 1 and 500 to 1 and a surface area of between 400 and 2630 m.sup.2/g. The nanocomposite material has a specific capacity at least twice that of a titania material without graphene material at a charge/discharge rate greater than about 10 C. The olivine structure of the cathode of the lithium ion battery of the present invention is LiMPO.sub.4 where M is selected from the group consisting of Fe, Mn, Co, Ni and combinations thereof.
Liu, Jun; Choi, Daiwon; Yang, Zhenguo; Wang, Donghai; Graff, Gordon L; Nie, Zimin; Viswanathan, Vilayanur V; Zhang, Jason; Xu, Wu; Kim, Jin Yong
Low-cost Precursors for In-situ Synthesis of Composite Materials ...
Symposium, J. Materials and Processes for Enhanced Performance ... Separation and Recovery Process of Rare Metals from Oil Desulfurization Spent Catalyst.
Composition of Toxic Leachate and Unstable Compost to Produce Biodegradable Material
Abstract: This paper reports a study of mixing two materials that were toxic leachate and unstable compost, aiming to produce biodegradable material. Various low levels of BOD/COD of leachate were mixed with various high levels of C/N of unstable compost. CO2 evolution test was performed to measure the degree of biodegradable materials. The leachate contained BOD and COD that were more than 100 and 500 mg LG 1 respectively and represented by BOD/COD ratio of less than 0.1. The compost characterized by C/N ratio in the range of 15-20. Results showed that leachate and compost mixture produced biodegradable material. A mixture containing 20 % leachate and 80 % compost produced high level of biodegradable material. Key words: Toxic leachate % Unstable compost % Biodegradable material
Sarwoko Mangkoedihardjo; Yulia Maghriba; Rachmat Boedisantoso
Method for rapid fabrication of fiber preforms and structural composite materials
A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50 C for 14 hours and hot pressed at 2000 psi at 400 C for 3 hours. The hot pressed part is carbonized at 650 C under nitrogen for 3 hours and graphitized at 2400 C to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc. 12 figs.
Klett, J.W.; Burchell, T.D.; Bailey, J.L.
A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50 C for 14 hours and hot pressed at 2,000 psi at 400 C for 3 hours. The hot pressed part is carbonized at 650 C under nitrogen for 3 hours and graphitized at 2,400 C to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc. 12 figs.
A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50.degree. C. for 14 hours and hot pressed at 2000 psi at 400.degree. C. for 3 hours. The hot pressed part is carbonized at 650.degree. C. under nitrogen for 3 hours and graphitized at 2400.degree. C. to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc.
Klett, James W. (Knoxville, TN); Burchell, Timothy D. (Oak Ridge, TN); Bailey, Jeffrey L. (Clinton, TN)
A densified carbon matrix carbon fiber composite preform is made by vacuum molding an aqueous slurry of carbon fibers and carbonizable organic powder to form a molded part. The molded part is dried in an oven at 50.degree. C. for 14 hours and hot pressed at 2000 psi at 400.degree. C. for 3 hours. The hot pressed part is carbonized at 650.degree. C. under nitrogen for 3 hours and graphite at 2400.degree. C. to form a graphitic structure in the matrix of the densified carbon matrix carbon fiber composite preform. The densified preform has a density greater than 1.1 g/cc.
Graphene as a Prototype Crystalline Membrane
The understanding of the structural and thermal properties of membranes, low-dimensional flexible systems in a space of higher dimension, is pursued in many fields from string theory to chemistry and biology. The case of a two-dimensional (2D) membrane in three dimensions is the relevant one for dealing with real materials. Traditionally, membranes are primarily discussed in the context of biological membranes and soft matter in general. The complexity of these systems hindered a realistic description of their interatomic structures based on a truly microscopic approach. Therefore, theories of membranes were developed mostly within phenomenological models. From the point of view of statistical mechanics, membranes at finite temperature are systems governed by interacting long-range fluctuations. Graphene, the first truly two-dimensional system consisting of just one layer of carbon atoms, provides a model system for the development of a microscopic description of membranes. In this Account, we review key results in the microscopic theory of structural and thermal properties of graphene and compare them with the predictions of phenomenological theories. The two approaches are in good agreement for the various scaling properties of correlation functions of atomic displacements. However, some other properties, such as the temperature dependence of the bending rigidity, cannot be understood based on phenomenological approaches. We also consider graphene at very high temperature and compare the results with existing models for two-dimensional melting. The melting of graphene presents a different scenario, and we describe that process as the decomposition of the graphene layer into entangled carbon chains.
Mikhail I. Katsnelson; Annalisa Fasolino
Role of material properties and mesostructure on dynamic deformation and shear instability in Al-W granular composites
Dynamic experiments with Al-W granular/porous composites revealed qualitatively different behavior with respect to shear localization depending on bonding between Al particles. Two-dimensional numerical modeling was used to explore the mesomechanics of the large strain dynamic deformation in Al-W granular/porous composites and explain the experimentally observed differences in shear localization between composites with various mesostructures. Specifically, the bonding between the Al particles, the porosity, the roles of the relative particle sizes of Al and W, the arrangements of the W particles, and the material properties of Al were investigated using numerical calculations. It was demonstrated in simulations that the bonding between the "soft" Al particles facilitated shear localization as seen in the experiments. Numerical calculations and experiments revealed that the mechanism of the shear localization in granular composites is mainly due to the local high strain flow of "soft" Al around the "rigid" W particles causing localized damage accumulation and subsequent growth of the meso/macro shear bands/cracks. The "rigid" W particles were the major geometrical factor determining the initiation and propagation of "kinked" shear bands in the matrix of "soft" Al particles, leaving some areas free of extensive plastic deformation as observed in experiments and numerical calculations.
K. L. Olney; P. H. Chiu; C. W. Lee; V. F. Nesterenko; D. J. Benson
Properties of Two Carbon Composite Materials Using LTM25 Epoxy Resin
In this report, the properties of two carbon-epoxy prepreg materials are presented. The epoxy resin used in these two materials can yield lower manufacturing costs due to its low initial cure temperature, and the capability of being cured using vacuum ...
Cruz J. R.; Shah C. H.; Postyn A. S.
Design of a novel conduction heating based stress-thermal cycling apparatus for composite materials and its utilization to characterize composite microcrack damage thresholds
The objective of this research was to determine the effect of thermal cycling combined with mechanical loading on the development of microcracks in M40J/PMR-II- 50, the second generation aerospace application material. The objective was pursued by finding the critical controlling parameters for microcrack formation from mechanical stress-thermal cycling test. Three different in-plane strains (0%, 0.175~0.350%, and 0.325~0.650%) were applied to the composites by clamping composite specimens (M40J/PMR-II-50, [0,90]s, a unitape cross-ply) on the radial sides of half cylinders having two different radii (78.74mm and 37.96mm). Three different thermal loading experiments, 1) 23oC to �196oC to 250oC, 2) 23oC to 250oC, and 3) 23oC to -196oC, were performed as a function of mechanical inplane strain levels, heating rates, and number of thermal cycles. The apparatus generated cracks related to the in-plane stresses (or strains) on plies. The design and analysis concept of the synergistic stress-thermal cycling experiment was simplified to obtain main and interaction factors by applying 2k factorial design from the various factors affecting microcrack density of M40J/PMR-II-50. Observations indicate that the higher temperature portion of the cycle under load causes fiber/matrix interface failure. Subsequent exposure to higher stresses in the cryogenic temperature region results in composite matrix microcracking due to the additional stresses associated with the fiber-matrix thermal expansion mismatch.
Ju, Jaehyung
Nanostructured thin film thermoelectric composite materials using conductive polymer PEDOT:PSS
Thermoelectric materials have the ability to convert heat directly into electricity. This clean energy technology has advantages over other renewable technologies in that it requires no sunlight, has no moving parts, and ...
Kuryak, Chris A. (Chris Adam)
Thermal Transport in Graphene Multilayers and Nanoribbons
1 CHAPTER 2 Thermal transport atvalues of graphene's thermal conductivity and different1 Thermal conductivity : metals and non - metallic
Subrina, Samia
Properties of Aluminum-Graphene Nanocomposites
With the exponential increase in attention given to graphene in current research arenas, we have chosen to study the addition of graphene platelets to an ...
First Observation of Plasmarons in Graphene First Observation of Plasmarons in Graphene Print Wednesday, 30 June 2010 00:00 An international team of scientists performing...
Structure, Defects, and Scattering in Graphene
Structure, Defects, and Scattering in Graphene. ... (b) STM image of a complex moiré pattern observed in multilayer graphene grown on SiC. ...
Renormalization group aspects of graphene
Graphene is a two dimensional crystal of carbon atoms with fascinating electronic and morphological properties. The low energy excitations of the neutral, clean system are described by a massless Dirac Hamiltonian in (2+1) dimensions which also captures the main electronic and transport properties. A renormalization group analysis sheds light on the success of the free model: due to the special form of the Fermi surface which reduces to two single points in momentum space, short range interactions are irrelevant and only gauge interactions like long range Coulomb or effective disorder can play a role in the low energy physics. We review these features and discuss briefly other aspects related to disorder and to the bilayer material along the same lines.
Maria A. H. Vozmediano
AC/AB Stacking Boundaries in Bilayer Graphene
Boundaries, including phase boundaries, grain boundaries, and domain boundaries, are known to have an important influence on material properties. Here, dark-field (DF) transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) imaging are combined to provide a full view of boundaries between AB and AC stacking domains in bilayer graphene across length scales from discrete atoms to the macroscopic continuum. Combining the images with results obtained by density functional theory (DFT) and classical molecular dynamics calculations, we demonstrate that the AB/AC stacking boundaries in bilayer graphene are nanometer-wide strained channels, mostly in the form of ripples, producing smooth low-energy transitions between the two different stackings. Our results provide a new understanding of the novel stacking boundaries in bilayer graphene, which may be applied to other layered two-dimensional materials as well.
Lin, Junhao [ORNL; Fang, Wenjing [Massachusetts Institute of Technology (MIT); Zhou, Wu [ORNL; Lupini, Andrew R [ORNL; Idrobo Tapia, Juan C [ORNL; Kong, Jing [Massachusetts Institute of Technology (MIT); Pennycook, Stephen J [ORNL; Pantelides, Sokrates T [ORNL
Fabrication and electrical characterization of transistors made from carbon nanotubes and graphene
Carbon nanotubes and graphene are low-dimensional allotropes of carbon which exhibit novel mechanical and electrical properties. The methods for producing these materials and fabricating electronic devices from them are ...
Nezich, Daniel Andrew
Towards the fabrication of suspended superconductor-graphene-superconductor Josephson junctions
Graphene, a newly discovered material. has been the subject of much experimental and theoretical study due to its unique electronic behavior. In this thesis, I present, my work with graduate student Joel Wang to design and ...
Wei, Haofei
Current efforts in standardization of composite materials testing for crashworthiness and energy
, the material system, and the impact velocity. The recently formed MIL-HDBK-17 Working Group (WG would like to thank the MIL-HDBK-17 Working Group, in particular Karen Jackson (Army Research) for their technical support. The author would also like to acknowledge Larry Ilcewicz (FAA, and chair-at-large of MIL-HDBK
Graphene Layer Growth: Collision of Migrating Five-Member Rings
Monte Carlo simulations of graphene edge buildup, the rateGraphene layer growth: Collision of migrating five- memberon the zigzag edge of a graphene layer. The process is
Whitesides, Russell; Kollias, Alexander C.; Domin, Dominik; Lester Jr., William A.; Frenklach, Michael
Graphene as the Ultimate Membrane for Gas Separation Project...
Graphene as the Ultimate Membrane for Gas Separation Graphene as the Ultimate Membrane for Gas Separation GraphenePore.jpg Key Challenges: Investigate the permeability and...
Nonlinear graphene plasmonics: amplitude equation
Using perturbation expansion of Maxwell equations, the amplitude equation is derived for nonlinear TM and TE surface plasmon waves supported by graphene. The equation describes interplay between in-plane beam diffraction and nonlinerity due to light intensity induced corrections to graphene conductivity and susceptibility of dielectrics. For strongly localized TM plasmons, graphene is found to bring the superior contribution to the overall nonlinearity. In contrast, nonlinear response of the substrate and cladding dielectrics can become dominant for weakly localized TE plasmons.
Gorbach, A V
The Influence of Graphene Curvature on Hydrogen Adsorption: Towards Hydrogen Storage Devices
The ability of atomic hydrogen to chemisorb on graphene makes the latter a promising material for hydrogen storage. Based on scanning tunneling microscopy techniques, we report on site-selective adsorption of atomic hydrogen on convexly curved regions of monolayer graphene grown on SiC(0001). This system exhibits an intrinsic curvature owing to the interaction with the substrate. We show that at low coverage hydrogen is found on convex areas of the graphene lattice. No hydrogen is detected on concave regions. These findings are in agreement with theoretical models which suggest that both binding energy and adsorption barrier can be tuned by controlling the local curvature of the graphene lattice. This curvature-dependence combined with the known graphene flexibility may be exploited for storage and controlled release of hydrogen at room temperature making it a valuable candidate for the implementation of hydrogen-storage devices.
Goler, Sarah; Tozzini, Valentina; Piazza, Vincenzo; Mashoff, Torge; Beltram, Fabio; Pellegrini, Vittorio; Heun, Stefan
Composition profiling of solar coating materials. Final report, April 16, 1976-April 15, 1979
Auger electron composition vs. depth and optical analysis revealed that a very inexpensive-to-produce (15 min. 900/sup 0/C heat treatment in air) Cr/sub 2/O/sub 3/ layer on stainless steels provides an excellent diffusion barrier for preventing stainless steel constituents from entering into an IR reflective Mo coating. It was shown that with sputter deposition of Mo at high rate in a clean noble gas plasma, one can obtain Mo coatings of excellent IR reflectance (> 96% between 2.5 and 25 ..mu..m wavelength). The optical properties (..cap alpha.. and epsilon) of various other absorber surfaces such as stacked razor blades, cone or whisker-covered metal surfaces, plasma-sprayed chromic oxide coatings etc. were measured and explored. (MOW)
Wehner, G.K.
mobility and other unique features hold great promise for nanoscale electronics and photonics. But without a bandgap, graphene's promise can't be realized. As with monolayer...
Magnetic Edge States in Graphene
Magnetic confinement in graphene has been of recent and growing interest because its potential applications in nanotechnology. In particular, the observation of the so called magnetic edge states in graphene has opened the possibility to deepen into the generation of spin currents and its applications in spintronics. We study the magnetic edge states of quasi-particles arising in graphene monolayers due to an inhomogeneous magnetic field of a magnetic barrier in the formalism of the two-dimensional massless Dirac equation. We also show how the solutions of such states in each of both triangular sublattices of the graphene are related through a supersymmetric transformation in the quantum mechanical sense.
Gabriela Murguia
Surprising Quasiparticle Interactions in Graphene
Surprising Quasiparticle Interactions in Graphene Print Until now, the world's electronics have been dominated by silicon, whose properties, while excellent, significantly limit...
Theory of Transport in Graphene
... Ideal graphene has the highest electron mobility of any ... giving rise to high electron and thermal ... due to interactions between the electrons and the ...
2009 00:00 Graphene is the two-dimensional crystalline form of carbon whose extraordinary electron mobility and other unique features hold great promise for nanoscale electronics...
Puzzling New Physics from Graphene Quartet's Quantum ...
Puzzling New Physics from Graphene Quartet's Quantum Harmonies. For Immediate Release: September 14, 2010. ...
'Tuning' Graphene Drums Might Turn Conductors to ...
'Tuning' Graphene Drums Might Turn Conductors to Semiconductors. From NIST Tech Beat: June 27, 2012. ...
Layered Graphene Sheets Could Solve Hydrogen Storage ...
Layered Graphene Sheets Could Solve Hydrogen Storage Issues. For Immediate Release: March 16, 2010. ...
Composite bearing and seal materials for advanced heat engine applications to 900 degree C
Plasma sprayed composite coatings of metal-bonded chromium carbide with additions of silver and thermochemically stable fluorides were previously reported to be lubricative in pin on disk bench tests from room temperature to 900{degree}C. An early coating formulation of this type, designated as PS200, was successfully tested as a cylinder coating in a Stirling engine at a TRRT of 760{degree}C (1450{degree}F) in a hydrogen atmosphere, and as a backup lubricant for gas bearings to 650{degree}C (1250{degree}F). A subsequent optimization program as shown that tribological properties are further improved by increasing the solid lubricant content. The improved coating is designated as PS212. The same powder formulation has been used to make free-standing powder metallurgy (PM212) parts by sintering or hot isostatic pressing. The process is very attractive for making parts that cannot be readily plasma sprayed such as bushings and cylinders that have small bore diameters and/or high length to diameter ratios. The properties of coatings and free-standing parts fabricated from these powders are reviewed. 6 refs., 14 figs., 1 tab.
Sliney, H.E.
Inch-Scale High Throughput Metrology of Graphene and Patterned Graphene Oxide
Strength of Monolayer Graphene Science 2008 321, 385-388. 5.Novoselov, K. S. The rise of graphene Nature 2007 6 183-191.A. Thermal properties of graphene and nanostructured carbon
Pleskot, Dennis
ESS 2012 Peer Review - Next Generation Composite Materials for Flywheel Development - Timothy Lambert, SNL
Sandia! Sandia! National! Laboratories! Acknowledgments We gratefully acknowledge support from Dr. Imre Gyuk and the Office of Electricity, Delivery and Energy Reliability. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the United States Department of Energy s National Nuclear Security Administration under contract DE-AC04-94AL85000. Abstract Flywheels are "mechanical battery" storage systems that have fast response times, long lifetimes and lower maintenance costs; when coupled with high-temperature superconducting (HTS) bearings, flywheels can exhibit extremely low rotational losses resulting in high efficiency. For energy storage purposes, materials with higher strengths, and lower densities that would allow the flywheel to spin
Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride, carbide and carbonitride
A composite material having high hardness comprises a carbon nitrogen compound, such as CN{sub x} where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN{sub x}. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45--55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating. 10 figs.
Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Chu, X.; Barnett, S.A.
Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride carbide and carbonitride
Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Xi Chu; Barnett, S.A.
Direct Imagining of Soft-hard Interfaces Enabled by Graphene
Direct Imagining of Soft-hard Interfaces Enabled by Graphene Direct Imagining of Soft-hard Interfaces Enabled by Graphene Title Direct Imagining of Soft-hard Interfaces Enabled by Graphene Publication Type Journal Article Year of Publication 2009 Authors Lee, Zonghoon, Ki-Joon Jeon, Albert Dato, Rolf Erni, Thomas J. Richardson, Michael Frenklach, and Velimir Radmilovic Journal NanoLetters Volume 9 Start Page 3365 Issue 9 Pagination 3365-3369 Date Published 09/2009 Abstract Direct imaging of surface molecules and the interfaces between soft and hard materials on functionalized nanoparticles is a great challenge using modern microscopy techniques. We show that graphene, a single atomic layer of sp2-bonded carbon atoms, can be employed as an ultrathin support film that enables direct imaging of molecular layers and interfaces in both conventional and atomic-resolution transmission electron microscopy. An atomic-resolution imaging study of the capping layers and interfaces of citrate-stabilized gold nanoparticles is used to demonstrate this novel capability. Our findings reveal the unique potential of graphene as an ideal support film for atomic-resolution transmission electron microscopy of hard and soft nanomaterials.
Many-body interactions in quasi-freestanding graphene
The Landau-Fermi liquid picture for quasiparticles assumes that charge carriers are dressed by many-body interactions, forming one of the fundamental theories of solids. Whether this picture still holds for a semimetal such as graphene at the neutrality point, i.e., when the chemical potential coincides with the Dirac point energy, is one of the long-standing puzzles in this field. Here we present such a study in quasi-freestanding graphene by using high-resolution angle-resolved photoemission spectroscopy. We see the electron-electron and electron-phonon interactions go through substantial changes when the semimetallic regime is approached, including renormalizations due to strong electron-electron interactions with similarities to marginal Fermi liquid behavior. These findings set a new benchmark in our understanding of many-body physics in graphene and a variety of novel materials with Dirac fermions.
Siegel, David; Park, Cheol-Hwan; Hwang, Choongyu; Deslippe, Jack; Fedorov, Alexei; Louie, Steven; Lanzara, Alessandra
Electrochemical method of producing nano-scaled graphene platelets
A method of producing nano-scaled graphene platelets with an average thickness smaller than 30 nm from a layered graphite material. The method comprises (a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction; (b) exposing the intercalated graphite compound to a thermal shock to produce exfoliated graphite; and (c) subjecting the exfoliated graphite to a mechanical shearing treatment to produce the nano-scaled graphene platelets. Preferred carboxylic acids are formic acid and acetic acid. The exfoliation step in the instant invention does not involve the evolution of undesirable species, such as NO.sub.x and SO.sub.x, which are common by-products of exfoliating conventional sulfuric or nitric acid-intercalated graphite compounds. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.
Zhamu, Aruna; Jang, Joan; Jang, Bor Z.
Quantum Field Theory in Graphene
This is a short non-technical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.
Fialkovsky, I V
I. V. Fialkovsky; D. V. Vassilevich
Turbulent flow in graphene
We demonstrate the possibility of a turbulent flow of electrons in graphene in the hydrodynamic region, by calculating the corresponding turbulent probability density function. This is used to calculate the contribution of the turbulent flow to the conductivity within a quantum Boltzmann approach. The dependence of the conductivity on the system parameters arising from the turbulent flow is very different from that due to scattering.
Kumar S. Gupta; Siddhartha Sen
Coulomb impurity in graphene
We consider the problem of screening of an electrically charged impurity in a clean graphene sheet. When electron-electron interactions are neglected, the screening charge has a sign opposite to that of the impurity, and is localized near the impurity. Interactions between electrons smear out the induced charge density to give a large-distance tail that follows approximately, but not exactly, an r^{-2} behavior and with a sign which is the same as that of the impurity.
Rudro R. Biswas; Subir Sachdev; Dam T. Son
Graphene: What Can Go Wrong? New Studies Point to ...
Graphene: What Can Go Wrong? New Studies Point to Wrinkles, Process Contaminants. Graphene: What Can Go Wrong? ...
Graphene nano-ribbon waveguides
Graphene as a one-atom-thick platform for infrared metamaterial plays an important role in optical science and engineering. Here we study the unique properties of some plasmonic waveguides based on graphene nano-ribbon. It is found that a graphene ribbon of finite width leads to the occurrence of coupled edge mode. The single-mode region of a single freestanding graphene ribbon is identified at a fixed frequency of 30 THz. A low-loss waveguide structure, consisting of a graphene layer, a silica buffer layer and silicon substrate is proposed to reduce the propagation loss and obtain a high figure of merit for future integration of waveguide devices. Furthermore, two coupled ribbon configurations, namely, side-side coupling and top-bottom coupling, are investigated. As a device example, a nano-ring cavity of ultra-small size is designed.
He, S; He, Y
Materials Materials and methods are available as supplementary materials on Science Online. 16. W. Benz, A. G. W. Cameron, H. J. Melosh, Icarus 81, 113 (1989). 17. S. L. Thompson, H. S. Lauson, Technical Rep. SC-RR-710714, Sandia Nat. Labs (1972). 18. H. J. Melosh, Meteorit. Planet. Sci. 42, 2079 (2007). 19. S. Ida, R. M. Canup, G. R. Stewart, Nature 389, 353 (1997). 20. E. Kokubo, J. Makino, S. Ida, Icarus 148, 419 (2000). 21. M. M. M. Meier, A. Reufer, W. Benz, R. Wieler, Annual Meeting of the Meteoritical Society LXXIV, abstr. 5039 (2011). 22. C. B. Agnor, R. M. Canup, H. F. Levison, Icarus 142, 219 (1999). 23. D. P. O'Brien, A. Morbidelli, H. F. Levison, Icarus 184, 39 (2006). 24. R. M. Canup, Science 307, 546 (2005). 25. J. J. Salmon, R. M. Canup, Lunar Planet. Sci. XLIII, 2540 (2012). Acknowledgments: SPH simulation data are contained in tables S2 to S5 of the supplementary materials. Financial support
Li(Ni{sub 0.4}Co{sub 0.15}Al{sub 0.05}Mn{sub 0.4})O{sub 2} was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. In situ X-ray absorption spectroscopy (XAS) was performed, utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range. (1.0-4.7 V) XAS measurements were performed at different states of charge (SOC) during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure (EXAFS) region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni{sup 2+}, Co{sup 3+}, and Mn{sup 4+} in the as-made material (fully discharged), while during charging the Ni{sup 2+} is oxidized to Ni{sup 4+} through an intermediate stage of Ni{sup 3+}, Co{sup 3+} is oxidized toward Co{sup 4+}, and Mn was found to be electrochemically inactive and remained as Mn{sup 4+}. The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O, and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.
Rumble, C.; Conry, T.E.; Doeff, Marca; Cairns, Elton J.; Penner-Hahn, James E.; Deb, Aniruddha
Self-assembled TiO2-Graphene Hybrid Nanostructures for Enhanced Li-ion Insertion
We used anionic sulfate surfactants to assist the stabilization of graphene in aqueous solutions and facilitate the self-assembly of in-situ grown nanocrystalline TiO2, rutile and anatase, with graphene. These nanostructured TiO2-graphene hybrid materials were used for investigation of Li-ion insertion properties. The hybrid materials showed significantly enhanced Li-ion insertion/extraction in TiO2. The specific capacity was more than doubled at high charge rates, as compared with the pure TiO2 phase. The improved capacity at high charge-discharge rate may be attributed to increased electrode conductivity in presence of a percolated graphene network embedded into the metal oxide electrodes.
Wang, Donghai; Choi, Daiwon; Li, Juan; Yang, Zhenguo; Nie, Zimin; Kou, Rong; Hu, Dehong; Wang, Chong M.; Saraf, Laxmikant V.; Zhang, Jiguang; Aksay, Ilhan A.; Liu, Jun
Discrete Breathers in Deformed Graphene
The linear and nonlinear dynamics of elastically deformed graphene have been studied. The region of the stability of a planar graphene sheet has been represented in the space of the two-dimensional strain (? xx, ? yy) with the x and y axes oriented in the zigzag and armchair directions, respectively. It has been shown that the gap in the phonon spectrum appears in graphene under uniaxial deformation in the zigzag or armchair direction, while the gap is not formed under a hydrostatic load. It has been found that graphene deformed uniaxially in the zigzag direction supports the existence of spatially localized nonlinear modes in the form of discrete breathers, the frequency of which decreases with an increase in the amplitude. This indicates soft nonlinearity in the system. It is unusual that discrete breather has frequency within the phonon spectrum of graphene. This is explained by the fact that the oscillation of the discrete breather is polarized in the plane of the graphene sheet, while the phonon spectral band where the discrete breather frequency is located contains phonons oscillating out of plane. The stability of the discrete breather with respect to the small out-of-plane perturbation of the graphene sheet has been demonstrated. DOI: 10.1134/S0021364011190106 1.
Enhanced Electrochemical Performance of Oxide-carbon Composite ...
Abstract Scope, Hierarchical oxide/carbon nanofiber composites with nanosized ... Engineering in Low Stacking Fault Energy Alloys on their Corrosion Resistance ... for Intrinsic Electrical Characterization of Graphene Filed-Effect Transistors.
Oxide/Graphene Nanocomposite Functional Materials
Rare Earth Activated Oxides for Solid State Lighting · Rare Earth Doped Tellurite and Chalcogenide Planar Waveguide Amplifiers and Lasers · Replacing ...
Dynamic properties of graphene
The phonon spectrum of graphene has been studied with the minimum set of the nearest neighbors in the Born-von Karman model taking into account the electron-electron and electron-phonon interactions. The widths, both natural and owing to interactions with defects, of phonons have been estimated. Symmetry constraints imposed on force constants are taken into account. For symmetry reasons, vibrations with the polarization normal to the plane of the layer are not related to in-plane vibrations. The phonon frequencies at symmetry points and elastic moduli are expressed in terms of force constants.
Fal'kovskii, L. A., E-mail: firstname.lastname@example.com [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)
Phonon dispersion in graphene
Taking into account the constraints imposed by the lattice symmetry, the phonon dispersion is calculated for graphene with interactions between the first and second nearest neighbors in the framework of the Born-von Karman model. Analytical expressions are obtained for the out-of-plane (bending) modes determined only by two force constants as well as for the in-plane modes with four force constants. Values of the force constants are found in fitting to elastic constants and Raman frequencies observed in graphite.
L. A. Falkovsky
Probing the electronic structure and optical response of a graphene quantum disk supported on monolayer graphene
different from either monolayer graphene or double-layer graphene. Highly localized plasmon modesV accelerating voltage, which is below the damage threshold of the perfect graphene lattice. After aberration carbon layer at the GQD, giving an integrated carbon signal twice as high as that from monolayer graphene
Pennycook, Steve
Chemical Vapor Deposition-Derived Graphene with Electrical Performance of Exfoliated Graphene
-effect mobility. These results confirm the possibility of achieving high-performance graphene devices based electrical performance comparable to that of high-quality exfoliated graphene. We grow single-layer graphene by more conventional CVD methods,1-3 which yield continuous films of polycrystal- line graphene with grain
Kim, Philip
Nanotube Composite Anode Materials
Increased battery capacity, safety, ... Electric and plug-in hybrid electric vehicles; Portable electronic devices; Medical devices; and
Green Composite Materials
Oct 30, 2013 ... In this study, we have mapped the surface charge of both wool and spider dragline silk fibersusing chemically specific high-resolution force ...
Functional Composite Materials
Feb 17, 2010 ... Session Chair: Nik Chawla, Arizona State University; Katsuyoshi ... easily applied after-market alternative to existing large displacement ...
Powder and Composite Materials
Aug 8, 2013... Yonsei University; Robert O'Donnell, CSIRO; Jie Liu, Duke University .... At the capture of neutron in wide energy spectrum, the (n, ?) reaction ...
Information about Materials Properties
Table 6Â Â Â Examples of materials information required during detail design...identification Material class (metal, plastic, ceramic composite) Material subclass Material industry designation Material product form Material condition designation (temper, heat treatment, etc.) Material specification Material alternative names Material component designations (composite/assembly)...
Electrostatic transfer of epitaxial graphene to glass.
We report on a scalable electrostatic process to transfer epitaxial graphene to arbitrary glass substrates, including Pyrex and Zerodur. This transfer process could enable wafer-level integration of graphene with structured and electronically-active substrates such as MEMS and CMOS. We will describe the electrostatic transfer method and will compare the properties of the transferred graphene with nominally-equivalent 'as-grown' epitaxial graphene on SiC. The electronic properties of the graphene will be measured using magnetoresistive, four-probe, and graphene field effect transistor geometries [1]. To begin, high-quality epitaxial graphene (mobility 14,000 cm2/Vs and domains >100 {micro}m2) is grown on SiC in an argon-mediated environment [2,3]. The electrostatic transfer then takes place through the application of a large electric field between the donor graphene sample (anode) and the heated acceptor glass substrate (cathode). Using this electrostatic technique, both patterned few-layer graphene from SiC(000-1) and chip-scale monolayer graphene from SiC(0001) are transferred to Pyrex and Zerodur substrates. Subsequent examination of the transferred graphene by Raman spectroscopy confirms that the graphene can be transferred without inducing defects. Furthermore, the strain inherent in epitaxial graphene on SiC(0001) is found to be partially relaxed after the transfer to the glass substrates.
Ohta, Taisuke; Pan, Wei; Howell, Stephen Wayne; Biedermann, Laura Butler; Beechem Iii, Thomas Edwin; Ross, Anthony Joseph, III
Multiple Layer Graphene Optical Modulator
Scientists at Berkeley Lab have developed a tiny optical modulator based on graphene, potentially leading to significantly improved data transmission speeds in digital communications. The extremely strong interaction between light and relativistic ...
Chiral Gauge Theory for Graphene
We construct a chiral gauge theory to describe fractionalization of fermions in graphene. Thereby we extend a recently proposed model, which relies on vortex formation. Our chiral gauge fields provide dynamics for the vortices and also couple to the fermions.
R. Jackiw; S. -Y. Pi
emerging materials - TMS
…plenary discussion. Energy and Security; Nuclear Materials; Fuel Cells; Materials for Alternative Energy Applications. Advanced Metallic Composites and ...
Four Dimensional Graphene
Mimicking pristine 2D graphene, we revisit the BBTW model for 4D lattice QCD given in ref.[5] by using the hidden SU(5) symmetry of the 4D hyperdiamond lattice H_4. We first study the link between the H_4 and SU(5); then we refine the BBTW 4D lattice action by using the weight vectors \\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4, \\lambda_5 of the 5-dimensional representation of SU(5) satisfying {\\Sigma}_i\\lambda_i=0. After that we study explicitly the solutions of the zeros of the Dirac operator D in terms of the SU(5) simple roots \\alpha_1, \\alpha_2, \\alpha_3, \\alpha_4 generating H_4; and its fundamental weights \\omega_1, \\omega_2, \\omega_3, \\omega_4 which generate the reciprocal lattice H_4^\\ast. It is shown, amongst others, that these zeros live at the sites of H_4^\\ast; and the continuous limit D is given by ((id\\surd5)/2) \\gamma^\\muk_\\mu with d, \\gamma^\\mu and k_\\mu standing respectively for the lattice parameter of H_4, the usual 4 Dirac matrices and the 4D wave vector. Other features such as differences with BBTW model as well as the link between the Dirac operator following from our construction and the one suggested by Creutz using quaternions, are also given. Keywords: Graphene, Lattice QCD, 4D hyperdiamond, BBTW model, SU(5) Symmetry.
L. B Drissi; E. H Saidi; M. Bousmina
Quantum search on graphene lattices
We present a continuous-time quantum search algorithm on a graphene lattice. This provides the sought-after implementation of an efficient continuous-time quantum search on a two-dimensional lattice. The search uses the linearity of the dispersion relation near the Dirac point and can find a marked site on a graphene lattice faster than the corresponding classical search. The algorithm can also be used for state transfer and communication.
Iain Foulger; Sven Gnutzmann; Gregor Tanner
Breakdown in the Wetting Transparency of Graphene
We develop a theory to model the van der Waals interactions between liquid and graphene, including quantifying the wetting behavior of a graphene-coated surface. Molecular dynamics simulations and contact angle measurements ...
Shih, Chih-Jen
Transverse electric plasmons in bilayer graphene
We predict the existence of transverse electric (TE) plasmons in bilayer graphene. We find that their plasmonic properties are much more pronounced in bilayer than in monolayer graphene, in a sense that they can get more ...
Jablan, Marinko
Science & Innovation » Innovation » America's Next Top Energy Science & Innovation » Innovation » America's Next Top Energy Innovator » America's Next Top Energy Innovator Challenge » Vorbeck Materials Corp. America's Next Top Energy Innovator Challenge 45458 likes Vorbeck Materials Corp. Pacific Northwest National Laboratory Vorbeck Materials was founded in 2006 to bring to market products using graphene, a sheet of carbon that is only a single atom thick. Graphene is the strongest material ever tested and is electrically and thermally conductive. In recent years, there has been significant interest and activity on graphene research and its potential applications. The Aksay Labs at Princeton University produced a patented method for manufacturing graphene at commercial scale. Vorbeck signed a worldwide license for the
Center for Nanophase Materials Sciences - Newsletter
Research Highlights Low-Temperature Exfoliation of Multilayer-Graphene Material from FeCl3 and CH3NO2 Co-Intercalated Graphite Compound Wujun Fu,a Jim Kiggans,b Steven H....
Geek-Up[5.13.2011]: Engineering Graphene | Department of Energy
Geek-Up[5.13.2011]: Engineering Graphene Geek-Up[5.13.2011]: Engineering Graphene Geek-Up[5.13.2011]: Engineering Graphene May 13, 2011 - 5:12pm Addthis BNL scientists Dong Su and Eric Stach | Photo Courtesy of Brookhaven National Laboratory BNL scientists Dong Su and Eric Stach | Photo Courtesy of Brookhaven National Laboratory Niketa Kumar Niketa Kumar Public Affairs Specialist, Office of Public Affairs What are the key facts? Supercapacitors store charge in the form of static electricity, rather than relying on chemistry. Scientists use activated graphene (a form of carbon) to make advanced supercapacitor devices that combine high storage capacity with quick energy release and unlimited recharge. The UT-Austin material's processing techniques are already readily scalable to industrial production and have the potential to improve energy
Stabilization of Graphene-Polyaniline Based Nanocomposite ...
Presentation Title, Stabilization of Graphene-Polyaniline Based Nanocomposite Electrodes Using Barium Strontium Titanate for Supercapacitor Application.
Functionalized Graphene Nanoroads for Quantum Well Device
Using density functional theory, a series of calculations of structural and electronic properties of Si-substituted graphene were conducted. Through substituting C atoms by Si atoms on graphene in the present study, we found that the band gap of graphene can be continuously tuned with differently substitutional concentration. To utilize such substitution-induced band gap changes, we proposed a special design to fabricate graphene-based quantum well device.
Zhou, Yungang; Yang, Ping; Wang, Zhiguo; Xiao, Hai Yan; Zu, Xiaotao T.; Sun, Xin; Khaleel, Mohammad A.; Gao, Fei
A graphene-based broadband optical modulator
... 6, a monolayer of graphene possesses a much stronger inter-bandopticaltransition,whichfindsapplicationsinnoveloptoelectro-nic devices such as ...
Highlights 2010 25 Towards controlled graphene properties
C, require high tem- peratures. To use graphene as the basis of field-effect transistors at room temperature methacrylate) layer. We fabricate the graphene samples from highly ordered pyrolytic graphite (HOPG field F (therefore, the same in-plane strain || with much smaller voltage. For V graphene
Cuniberti, Gianaurelio
Optical Properties of Graphene and Graphene Nanoribbons
About this Abstract. Meeting, The 7th Pacific Rim International Conference on Advanced Materials and Processing (PRICM 7). Symposium, Symposium D: Bulk ...
Bound States in Graphene
We present a quantum analysis of the massless excitations in graphene with a charge impurity. When the effective charge exceeds a certain critical value, the spectrum is quantized and is unbounded from below. The corresponding eigenstates are square-integrable at infinity and have a rapidly oscillatory behaviour in the short distance, which can be interpreted as a fall to the centre. Using a cutoff regularization, we show that the effective Coulomb interaction strength is driven to its critical value under the renormalization group flow. In the subcritical region, we find bound states with imaginary values of the energy for certain range of the system parameters. The physical significance of these bound states with imaginary eigenvalues is discussed.
Materials testing and development of functionally graded composite fuel cladding and piping for the Lead-Bismuth cooled nuclear reactor
This study has extended the development of an exciting technology which promises to enable the Pb-Bi eutectic cooled reactors to operate at temperatures up to 650-700°C. This new technology is a functionally graded composite ...
Fray, Elliott Shepard
Graphene growth with giant domains using chemical vapor deposition
N. Martensson, Controlling graphene corrugation on lattice-in patterned epitaxial graphene, Science, 2006, 312(5777), 92009, 4(6), 17 A. K. Geim, Graphene: Status and Prospects,
Yong, Virginia; Hahn, H. Thomas
Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction
25-28, 2007. Topic: Soot GRAPHENE LAYER GROWTH CHEMISTRY:on the zigzag edge of a graphene layer isomerizes to reversea possibly important step in graphene layer growth, thus
Whitesides, Russell; Domin, Dominik; Lester Jr., William A.; Frenklach, Michael
Graphene Growth by Metal Etching on Ru (0001)
of step etching during graphene growth, such as in Fig. 3,adsorption of water on graphene structures will be describedRu(0001) Figure 5. a b c graphene Ru d Figure 6. Figure 7. a
Loginova, Elena
are incorporated into growing graphene layers and hence willGRAPHENE LAYER GROWTH CHEMISTRY: FIVE-SIX-RING FLIP REACTIONon the zigzag edge of a graphene layer. A new reaction
Whitesides, R.; Domin, D.; Salomon-Ferrer, R.; Lester Jr., W.A.; Frenklach, M.
A supersymmetric model for graphene
In this work, we focus on the fermionic structure of the low-energy excitations of graphene (a monolayer of carbon atoms) to propose a new supersymmetric field-theoretic model for this physical system. In the current literature, other proposals for describing graphene physics have been contemplated at the level of supersymmetric quantum mechanics. Also, by observing the inhomogeneities between neighbor carbon atoms, Jackiw et al. have set up an interesting chiral Abelian gauge theory. We show in this paper that our formulation encompasses models discussed previously as sectors of an actually richer (supersymmetric) planar gauge model. Possible interpretations for the fields involved in the present graphene model are proposed and the question of supersymmetry breaking is discussed.
Everton M. C. Abreu; Marco A. De Andrade; Leonardo P. G. de Assis; Jose A. Helayel-Neto; A. L. M. A. Nogueira; Ricardo C. Paschoal
The Schwinger mechanism and graphene
The Schwinger mechanism, the production of charged particle-antiparticle pairs in a macroscopic external electric field, is derived for 2+1 dimensional theories. The rate of pair production per unit area for four species of massless fermions, with charge $q$, in a constant electric field $E$ is given by $ \\pi^{-2} \\hbar^{-3/2} \\tilde{c}^{-1/2} (q E)^{3/2} $ where $\\tilde{c}$ is the speed of light for the two-dimensional system. To the extent undoped graphene behaves like the quantum field-theoretic vacuum for massless fermions in 2+1 dimensions, the Schwinger mechanism should be testable experimentally. A possible experimental configuration for this is proposed. Effects due to deviations from this idealized picture of graphene are briefly considered. It is argued that with present day samples of graphene, tests of the Schwinger formula may be possible.
Danielle Allor; Thomas D. Cohen; David A. McGady
Physisorption of Nucleobases on Graphene
We report the results of our first-principles investigation on the interaction of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) with graphene, carried out within the density functional theory framework, with additional calculations utilizing Hartree--Fock plus second-order Moeller-Plesset perturbation theory. The calculated binding energy of the nucleobases shows the following hierarchy: G > T ~ C ~ A > U, with the equilibrium configuration being very similar for all five of them. Our results clearly demonstrate that the nucleobases exhibit significantly different interaction strengths when physisorbed on graphene. The stabilizing factor in the interaction between the base molecule and graphene sheet is dominated by the molecular polarizability that allows a weakly attractive dispersion force to be induced between them. The present study represents a significant step towards a first-principles understanding of how the base sequence of DNA can affect its interaction with carbon nanotubes, as observed experimentally.
S. Gowtham; Ralph H. Scheicher; Rajeev Ahuja; Ravindra Pandey; Shashi P. Karna
Detection of hydrogen using graphene
Irradiation dynamics of a single graphene sheet bombarded by hydrogen atoms is studied in the incident energy range of 0.1 to 200 eV. Results for reflection, transmision, and adsorption probabilities, as well as effects of a sinle adsorbed atom to the electronic properties of graphene, are obtained by the quantum-classical Monte Carlo molecular dynamics within a self-consistent-charge-density functional tight binding formalism. We compare these results with those, distinctly different, obtained by the classical molecular dynamics.
Ehemann, R. C. [Middle Tennessee State University; Krstic, Predrag S [ORNL; Dadras, J. [University of Tennessee, Knoxville (UTK); Kent, P. [Oak Ridge National Laboratory (ORNL); Jakowski, J [National Institute for Computational Sciences (NICS)
Few-Layer Graphene as a Dry Lubricant
graphene layer is providing protection from high wear and steel corrosion. Scanning electron microscope image of as deposited graphene flakes (a) and Raman spectrum of one of...
Nitrogen-doped Graphene and Its Electrochemical Applications
Nitrogen-doped graphene (N-graphene) is obtained by exposing graphene to nitrogen plasma. N-graphene exhibits much higher electrocatalytic activity toward oxygen reduction and H2O2 reduction than graphene, and much higher durability and selectivity than the widely-used expensive Pt. The excellent electrochemical performance of N-graphene is attributed to nitrogen functional groups and the specific properties of graphene. This indicates that N-graphene is promising for applications in electrochemical energy devices (fuel cells, metal-air batteries) and biosensors.
Shao, Yuyan; Zhang, Sheng; Engelhard, Mark H.; Li, Guosheng; Shao, Guocheng; Wang, Yong; Liu, Jun; Aksay, Ilhan A.; Lin, Yuehe
Two Graphene Layers May Be Better Than One
Two Graphene Layers May Be Better Than One. From NIST Tech Beat: April 26, 2011. ... Microscopic polarization in bilayer graphene. Nature Physics. ...
Real-World Graphene Devices May Have a Bumpy Ride
... state of the graphene, the high electron mobility should make ... graphene, creating wells where the electrons pool and reducing their mobility.". ...
Engineering holographic graphene
We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS{sub 5} Multiplication-Sign S{sup 5}, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which can be viewed as a particular deformation of Coulomb interacting graphene, a parity and time reversal violating but gapless field theory and a system with a parity and time reversal violating charge gap. We show that the Chern-Simons-like electric response function, which is generated perturbatively at one-loop order by parity violating fermions and which is protected by a no-renormalization theorem at orders beyond one loop, indeed appears with the correctly quantized coefficient in the charge gapped theory. In the gapless parity violating solution, the Chern-Simons response function obtains quantum corrections which we compute in the holographic theory.
Semenoff, Gordon W. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada)
Functional Materials for Energy | Advanced Materials | ORNL
Energy Storage Fuel Cells Thermoelectrics Separations Materials Catalysis Sensor Materials Polymers and Composites Carbon Fiber Related Research Chemistry and Physics at...
Effect of energetic electron irradiation on graphene and graphene field-effect transistors
studies report on graphene's very high electrical conductivity1,2 at room temperature, and it is discussed://spiedl.org/terms #12;Our graphene samples are fabricated by micromechanical exfoliation1 of highly ordered pyrolytic ) and "high" (DOS > 800 e- /nm2 ) defect densities (referred to as "nanocrystalline graphene" and "mainly sp2
Chen, Yong P.
Surprising Quasiparticle Interactions in Graphene Print Surprising Quasiparticle Interactions in Graphene Print Until now, the world's electronics have been dominated by silicon, whose properties, while excellent, significantly limit the size and power consumption of today's computer chips. In order to develop ever smaller and more efficient devices, scientists have turned their attention to carbon, which can be formed into nanostructures like nanotubes, whose properties can be tuned from metallic to semiconducting. However, using carbon nanotubes for complex circuits is nearly impossible because their location and functionality in devices cannot be controlled at will, making them a poor substitute for silicon. Graphene, however, does not have these limitations. This single sheet of carbon atoms that is the building block of carbon nanotubes, C60 molecules, and graphite turns out to have similar functionality but with the added benefit that it can be grown with conventional methods and patterned into devices. Now, a group of scientists from Germany and the ALS, using angle-resolved photoemission spectroscopy (ARPES) at ALS Beamine 7.0.1, have succeeded in making the first measurement of the carrier lifetime in graphene over a wide energy scale and have found surprising new interactions that suggest new kinds of devices.
Surprising Quasiparticle Surprising Quasiparticle Interactions in Graphene Surprising Quasiparticle Interactions in Graphene Print Wednesday, 31 October 2007 00:00 Until now, the world's electronics have been dominated by silicon, whose properties, while excellent, significantly limit the size and power consumption of today's computer chips. In order to develop ever smaller and more efficient devices, scientists have turned their attention to carbon, which can be formed into nanostructures like nanotubes, whose properties can be tuned from metallic to semiconducting. However, using carbon nanotubes for complex circuits is nearly impossible because their location and functionality in devices cannot be controlled at will, making them a poor substitute for silicon. Graphene, however, does not have these limitations. This single sheet of carbon atoms that is the building block of carbon nanotubes, C60 molecules, and graphite turns out to have similar functionality but with the added benefit that it can be grown with conventional methods and patterned into devices. Now, a group of scientists from Germany and the ALS, using angle-resolved photoemission spectroscopy (ARPES) at ALS Beamine 7.0.1, have succeeded in making the first measurement of the carrier lifetime in graphene over a wide energy scale and have found surprising new interactions that suggest new kinds of devices.
Low Temperature Direct Growth of Graphene Films on Transparent Substrates by Chemical Vapor Deposition
innovative designs using graphene in fields like electronicsof Entire CVD- Grown Graphene Sheets", Small 7(18): 2599-dimensional few layer graphene and carbon nanotube foam
Antoine, Geoffrey Sandosh Jeffy
Electrostatic force assisted deposition of graphene
An embodiment of a method of depositing graphene includes bringing a stamp into contact with a substrate over a contact area. The stamp has at least a few layers of the graphene covering the contact area. An electric field is developed over the contact area. The stamp is removed from the vicinity of the substrate which leaves at least a layer of the graphene substantially covering the contact area.
Liang, Xiaogan (Berkeley, CA)
Available Technologies: Sulfur-Graphene Oxide Nanocomposite ...
A Berkeley Lab team headed by Yuegang Zhang and Elton Cairns has developed a method to fabricate battery cathodes from nanoscale flakes of graphene ...
Students SURF for Graphene at NIST
... signed on to be a part of NIST's graphene project, an agency ... Brian Bolz of Manhattan College looked into systematically controlling the deposition ...
Graphene Drumheads Tuned to Make Quantum Dots
... Able to conduct electricity with little resistance at room temperature, graphene is a prime candidate for applications ranging from flexible displays to ...
80 CHAPTER 5 Heat Conduction in Few Layerto Fourier's Law of heat conduction, thermal conductivity isnext experiments on heat conduction in graphene structures
Data Transmission Performance of Graphene Interconnects
We are continuously improving the quality of CVD grown graphene layers to improve the bandwidth of transmission beyond the gigabits per second level.
First Observation of Plasmarons in Graphene Print An international team of scientists performing angle-resolved photoemission spectroscopy (ARPES) experiments at ALS Beamline 7.0.1...
Graphene Encapsulated Gold Nanoparticles and Their Chemical ...
We have developed a robust batch-production method to synthesize graphene encapsulated AuNPs. Patterned AuNPs on a silicon substrate were utilized as ...
Electrical spin injection and transport in germanium". Phys.P. , Temperature- Dependent Transport in Suspended Graphene.Y. M. , Quantum Transport: Introduction to Nanoscience.
1 CHAPTER 2 Thermal transport atxix List of Tables Phonon transport regimes – Length scaleRIVERSIDE Thermal Transport in Graphene Multilayers and
SLAC National Accelerator Laboratory - Molecular Graphene Heralds...
Press Release Archive Molecular Graphene Heralds New Era of 'Designer Electrons' March 14, 2012 Menlo Park, Calif. - Researchers from Stanford University and the U.S. Department of...
Computer-Aided Materials Selection
Table 42Â Â Â Examples of materials information required during product design...identification Material class (metal, plastic, ceramic, composite) Material subclass Material industry designation Material product form Material condition designation (temper, heat treatment, etc.) Material specification Material alternative names Material component designations (composite/assembly)...
Electrical Control of Optical Plasmon Resonance with Graphene Jonghwan Kim,
free carrier response but also the high-frequency interband transition in graphene can be conveniently applied gate voltages. Rayleigh scattering intensity from an individual graphene- nanorod hybrid structure|. This is a direct consequence of blocked graphene optical absorption in highly doped graphene, which leads
Zettl, Alex
Materials characterization of silicon carbide reinforced titanium (Ti/SCS-6) metal matrix composites. Part 1: Tensile and fatigue behavior
Flexural fatigue behavior was investigated on titanium (Ti-15V-3Cr) metal matrix composites reinforced with cross-ply, continuous silicon carbide (SiC) fibers. The titanium composites had an eight-ply (0, 90, +45, {minus}45 deg) symmetric layup. Fatigue life was found to be sensitive to fiber layup sequence. Increasing the test temperature from 24 C to 427 C decreased fatigue life. Interface debonding and matrix and fiber fracture were characteristic of tensile behavior regardless of test temperature. In the tensile fracture process, interface debonding between SiC and the graphite coating and between the graphite coating and the carbon core could occur. A greater amount of coating degradation at 427 C than at 24 C reduced the Ti/SiC interface bonding integrity, which resulted in lower tensile properties at 427 C. During tensile testing, a crack could initiate from the debonded Ti/SiC interface and extend to the debonded interface of the neighboring fiber. The crack tended to propagate through the matrix and the interface. Dimpled fracture was the prime mode of matrix fracture. Interface debonding, matrix cracking, and fiber bridging were identified as the prime modes of fatigue mechanisms. To a lesser extent, fiber fracture was observed during fatigue. However, fiber fracture was believed to occur near the final stage of fatigue failure. In fatigued specimens, facet-type fracture appearance was characteristic of matrix fracture morphology. Theoretical modeling of the fatigue behavior of Ti/SCS-6 composites is presented in Part 2 of this series of articles.
Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Diaz, E.S. [Westinghouse Science and Technology Center, Pittsburgh, PA (United States); Chiang, K.T.; Loh, D.H. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.
Performance investigation on a novel two-stage solar driven rotary desiccant cooling system using composite desiccant materials
In this study, a two-stage solar driven rotary desiccant cooling (TSRDC) system with novel configuration and newly developed silica gel-haloid composite desiccant is proposed aiming to reduce regeneration temperature and to achieve high energy performance. Simulated results show that there also exists an optimal rotation speed for TSRDC system. Compared with one-stage system, it is found that for the similar supply air state, the required regeneration temperature of TSRDC system is lower and for the same regeneration temperature, the cooling capacity of TSRDC is bigger. (author)
Ge, T.S.; Li, Y.; Dai, Y.J.; Wang, R.Z. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240 (China)
Studying the sintering behavior of BeO{sub x}-SiC{sub 1-x} Composite ceramic Material
The sintering behavior for BeO-SiC compacts composite ceramic at different sintering temperatures in air were conducted, resulting data indicated that the percentage of SiC (Wt% 5) sintered at 800 C deg. lead to higher sintering density of (1.80 gm/cm3). The x-ray diffraction pattern analysis indicated nothing change concerning the crystal structure. Microstructure development has been studied as a function SiC content. Silicon carbide found to be suppressed the sinter ability of the matrix BeO powder.
Issa, Tarik Talib [Department of physics, College of Science, University of Baghdad, Jadiriya, Baghdad (Iraq)
Center for Nanophase Materials Sciences (CNMS) - CNMS Research
Low-temperature Exfoliation of Multilayer-Graphene Material from FeCl3 and CH3NO2 Co-intercalated Graphite Compound Wujun Fu,a Jim Kiggans,b Steven H. Overbury,a,c Viviane...
Advances in Two-dimensional Materials Research: From Dancing...
Phone:865.574.5035 Add to Calendar SHARE New low-dimensional materials such as graphene and hexagonal boron nitride (hBN) have opened up new opportunities in experimental...
Electronic structure of graphene oxide and reduced graphene oxide monolayers
Graphene oxide (GO) monolayers obtained by Langmuir Blodgett route and suitably treated to obtain reduced graphene oxide (RGO) monolayers were studied by photoelectron spectroscopy. Upon reduction of GO to form RGO C1s x-ray photoelectron spectra showed increase in graphitic carbon content, while ultraviolet photoelectron spectra showed increase in intensity corresponding to C2p-{pi} electrons ({approx}3.5 eV). X-ray excited Auger transitions C(KVV) and plasmon energy loss of C1s photoelectrons have been analyzed to elucidate the valence band structure. The effective number of ({pi}+{sigma}) electrons as obtained from energy loss spectra was found to increase by {approx}28% on reduction of GO.
Sutar, D. S. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Central Surface Analytical Facility, Indian Institute of Technology Bombay, Mumbai 400076 (India); Singh, Gulbagh; Divakar Botcha, V. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India)
Harnessing vacuum forces for quantum sensing of graphene motion
The existence of vacuum forces is one of the most striking consequences of quantum mechanics. We show how the strong potentials induced by vacuum fluctuations can be exploited in a practical scheme for quantum sensing. Position measurements at the quantum level are of central importance for many applications but very challenging. Typically, methods based on optical forces are used, but these are generally weak and difficult to apply to many materials. An important example is graphene, which is an excellent mechanical resonator due to its low mass and whose unique properties render it an outstanding platform for nanotechnologies. We describe a protocol wherein quantum vacuum potentials yield a strong dispersive interaction between the displacement of a graphene nanomechanical resonator and a nearby quantum optical emitter. This interaction yields a large position-dependent shift in the transition frequency of the emitter, which can be read out via an optical field. Under realistic conditions, we show that this mechanism enables strong quantum squeezing of the graphene position on time scales short compared to the mechanical period.
Christine A. Muschik; Simon Moulieras; Maciej Lewenstein; Frank Koppens; Darrick Chang
Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene
The electronic bandgap is an intrinsic property of semiconductors and insulators that largely determines their transport and optical properties. As such, it has a central role in modern device physics and technology and governs the operation of semiconductor devices such as p-n junctions, transistors, photodiodes and lasers. A tunable bandgap would be highly desirable because it would allow great flexibility in design and optimization of such devices, in particular if it could be tuned by applying a variable external electric field. However, in conventional materials, the bandgap is fixed by their crystalline structure, preventing such bandgap control. Here we demonstrate the realization of a widely tunable electronic bandgap in electrically gated bilayer graphene. Using a dual-gate bilayer graphene field-effect transistor (FET) and infrared microspectroscopy, we demonstrate a gate-controlled, continuously tunable bandgap of up to 250 meV. Our technique avoids uncontrolled chemical doping and provides direct evidence of a widely tunable bandgap -- spanning a spectral range from zero to mid-infrared -- that has eluded previous attempts. Combined with the remarkable electrical transport properties of such systems, this electrostatic bandgap control suggests novel nanoelectronic and nanophotonic device applications based on graphene.
Zhang, Yuanbo; Tang, Tsung-Ta; Girit, Caglar; Hao, Zhao; Martin, Michael C.; Zettl, Alex; Crommie, Michael F.; Shen, Y. Ron; Wang, Feng
Method for the production of {sup 99m}Tc compositions from {sup 99}Mo-containing materials
An improved method is described for producing {sup 99m}Tc compositions from {sup 99}Mo compounds. {sup 100}Mo metal or {sup 100}MoO{sub 3} is irradiated with photons in a particle (electron) accelerator to ultimately produce {sup 99}MoO{sub 3}. This composition is then heated in a reaction chamber to form a pool of molten {sup 99}MoO{sub 3} with an optimum depth of 0.5--5 mm. A gaseous mixture thereafter evolves from the molten {sup 99}MoO{sub 3} which contains vaporized {sup 99}MoO{sub 3}, vaporized {sup 99m}TcO{sub 3}, and vaporized {sup 99m}TcO{sub 2}. This mixture is then combined with an oxidizing gas (O{sub 2(g)}) to generate a gaseous stream containing vaporized {sup 99m}Tc{sub 2}O{sub 7} and vaporized {sup 99}MoO{sub 3}. Next, the gaseous stream is cooled in a primary condensation stage in the reaction chamber to remove vaporized {sup 99}MoO{sub 3}. Cooling is undertaken at a specially-controlled rate to achieve maximum separation efficiency. The gaseous stream is then cooled in a sequential secondary condensation stage to convert vaporized {sup 99m}Tc{sub 2}O{sub 7} into a condensed {sup 99m}Tc-containing reaction product which is collected. 1 fig.
Bennett, R.G.; Christian, J.D.; Grover, S.B.; Petti, D.A.; Terry, W.K.; Yoon, W.Y.
Electrochemical Kinetics and Performance of Layered Composite Cathode Material Li[Li0.2Ni0.2Mn0.6]O2
Lithium-rich, manganese-rich (LMR) layered composite cathode material Li[Li0.2Ni0.2Mn0.6]O2 has been successfully prepared by a co-precipitation method and its structure is confirmed by XRD characterization. The material delivers a high discharge capacity of 281 mAh g-1, when charged and discharged at a low current density of 10 mA g-1. However, significant increase of cell polarization and decrease of discharge capacity are observed at voltages below 3.5 V with increasing current densities. Galvanostatic intermittent titration technique (GITT) analysis demonstrates that lithium ion intercalation/de-intercalation reactions in this material are kinetically controlled by Li2MnO3 and its activated MnO2 component. The relationship between the electrochemical kinetics and rate performance as well as cycling stability has been systematically investigated. High discharge capacity of 149 mAh g-1 can be achieved at 10 C charge rate and C/10 discharge rate. The result demonstrates that the Li2MnO3 based material could withstand high charge rate (except initial activation process), which is very promising for practical applications. A lower discharge current density is preferred to overcome the kinetic barrier of lithium ion intercalation into MnO2 component, in order to achieve higher discharge capacity even at high charge rates.
Zheng, Jianming; Shi, Wei; Gu, Meng; Xiao, Jie; Zuo, Pengjian; Wang, Chong M.; Zhang, Jiguang
Hydrogen adsorption at the graphene surface: A vdW-DF perspective
We use the recently developed van der Waals density functional (vdW-DF) along with the C09x exchange functional to explore the interactions of molecular hydrogen with a single sheet of graphene. Our calculations demonstrate the importance of the inclusion of dispersion interactions for evaluating the adsorption capacity of graphitic, sparsely packed materials. In particular we show that, although the commonly used local density approximation (LDA) exchange-correlation functional gives reasonable H$_2$-graphene separation distances, these interactions are in fact too strong and decrease too rapidly as the H$_2$-graphene distance increases. On the other hand, calculations employing the generalized gradient approximation (GGA) for exchange and correlation exhibit very little binding. The vdW-DF$^{\\rm C09x}$ functional, however, gives binding very similar to benchmark second-order M$\\o$ller-Plesset (MP2) theory results for the H$_2$-coronene interaction and has an appropriate long range interaction with the graphene sheet. This shortcoming of the LDA and GGA functionals is shown to have significant consequences on the overall adsorption densities of H$_2$ near the graphene, thus emphasizing the fundamental importance of properly characterizing the interactions of adsorbed molecules in porous media.
Cooper, Valentino R [ORNL; Ihm, Yungok [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Morris, James R [ORNL
Emergent Horava gravity in graphene
First of all, we reconsider the tight - binding model of monolayer graphene, in which the variations of the hopping parameters are allowed. We demonstrate that the emergent 2D Weitzenbock geometry as well as the emergent U(1) gauge field appear. The emergent gauge field is equal to the linear combination of the components of the zweibein. Therefore, we actually deal with the gauge fixed version of the emergent 2+1 D teleparallel gravity. In particular, we work out the case, when the variations of the hopping parameters are due to the elastic deformations, and relate the elastic deformations with the emergent zweibein. Next, we investigate the tight - binding model with the varying intralayer hopping parameters for the multilayer graphene with the ABC stacking. In this case the emergent 2D Weitzenbock geometry and the emergent U(1) gauge field appear as well, the emergent low energy effective field theory has the anisotropic scaling.
G. E. Volovik; M. A. Zubkov
Chiral Symmetry Breaking in Graphene
The question of whether the Coulomb interaction is strong enough to break the sublattice symmetry of un-doped graphene is discussed. We formulate a strong coupling expansion where the ground state of the Coulomb Hamiltonian is found exactly and the kinetic hopping Hamiltonian is treated as a perturbation. We argue that many of the properties of the resulting system would be shared by graphene with a Hubbard model interaction. In particular, the best candidate sublattice symmetry breaking ground state is an antiferromagnetic Mott insulator. We discuss the results of some numerical simulations which indicate that the Coulomb interaction is indeed subcritical. We also point out the curious fact that, if the electron did not have spin degeneracy, the tendency to break chiral symmetry would be much greater and even relatively weak Coulomb interactions would likely gap the spectrum.
Gordon W. Semenoff
Smooth electron waveguides in graphene
We present exact analytical solutions for the zero-energy modes of two-dimensional massless Dirac fermions fully confined within a smooth one-dimensional potential V(x)= - {\\alpha}/cosh({\\beta}x), which provides a good fit for potential profiles of existing top-gated graphene structures. We show that there is a threshold value of the characteristic potential strength {\\alpha}/{\\beta} for which the first mode appears, in striking contrast to the non-relativistic case. A simple relationship between the characteristic strength and the number of modes within the potential is found. An experimental setup is proposed for the observation of these modes. The proposed geometry could be utilized in future graphene-based devices with high on/off current ratios.
R. R. Hartmann; N. J. Robinson; M. E. Portnoi
IOMMMS Global Materials Forum
Natural Fiber Composites – Significant Contribution to a Green Economy · Recent Development of Materials for Green Energy in Korea · The Role of Materials ...
A comparison of graphene, superconductors and metals as conductors for metamaterials and plasmonics
Recent advancements in metamaterials and plasmonics have promised a number of exciting applications, in particular at terahertz and optical frequencies. Unfortunately, the noble metals used in these photonic structures are not particularly good conductors at high frequencies, resulting in significant dissipative loss. Here, we address the question of what is a good conductor for metamaterials and plasmonics. For resonant metamaterials, we develop a figure-of-merit for conductors that allows for a straightforward classification of conducting materials according to the resulting dissipative loss in the metamaterial. Application of our method predicts that graphene and high-T{sub c} superconductors are not viable alternatives for metals in metamaterials. We also provide an overview of a number of transition metals, alkali metals and transparent conducting oxides. For plasmonic systems, we predict that graphene and high-T{sub c} superconductors cannot outperform gold as a platform for surface plasmon polaritons, because graphene has a smaller propagation length-to-wavelength ratio.
Tassin, Philippe; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas
Free Energy Relationships in the Electrical Double Layer over Single-Layer Graphene
Fluid/solid interfaces containing singlelayer graphene are important in the areas of chemistry, physics, biology, and materials science, yet this environment is difficult to access with experimental methods, especially under flow conditions and in a label-free manner. Herein, we demonstrate the use of second harmonic generation to quantify the interfacial free energy at the fused silica/single-layer graphene/water interface at pH 7 and under conditions of flowing aqueous electrolyte solutions ranging in NaCl concentrations from 10 4 to 10 1 M. Our analysis reveals that single-layer graphene reduces the interfacial free energy density of the fused silica/water interface by a factor of up to 7, which is substantial given that many interfacial processes, including those that are electrochemical in nature, are exponentially sensitive to interfacial free energy density.
Achtyl, Jennifer L. [Northwestern University, Evanston; Vlassiouk, Ivan V [ORNL; Fulvio, Pasquale F [ORNL; Mahurin, Shannon Mark [ORNL; Dai, Sheng [ORNL; Geiger, Franz M. [Northwestern University, Evanston
Quantized conductance of a suspended graphene nanoconstriction
A yet unexplored area in graphene electronics is the field of quantum ballistic transport through graphene nanostructures. Recent developments in the preparation of high mobility graphene are expected to lead to the experimental verification and/or discovery of many new quantum mechanical effects in this field. Examples are effects due to specific graphene edges, such as spin polarization at zigzag edges of a graphene nanoribbon and the use of the valley degree of freedom in the field of graphene valleytronics8. As a first step in this direction we present the observation of quantized conductance at integer multiples of 2e^2/h at zero magnetic field and 4.2 K temperature in a high mobility suspended graphene ballistic nanoconstriction. This quantization evolves into the typical quantum Hall effect for graphene at magnetic fields above 60mT. Voltage bias spectroscopy reveals an energy spacing of 8 meV between the first two subbands. A pronounced feature at 0.6 2e^2/h present at a magnetic field as low as ~0.2T resembles the "0.7 anomaly" observed in quantum point contacts in a GaAs-AlGaAs two dimensional electron gas, having a possible origin in electron-electron interactions.
Nikolaos Tombros; Alina Veligura; Juliane Junesch; Marcos H. D. Guimarăes; Ivan J. Vera Marun; Harry T. Jonkman; Bart J. van Wees
The Quantum Hall Effect in Graphene
We investigate the quantum Hall effect in graphene. We argue that in graphene in presence of an external magnetic field there is dynamical generation of mass by a rearrangement of the Dirac sea. We show that the mechanism breaks the lattice valley degeneracy only for the $n=0$ Landau levels and leads to the new observed $\
Paolo Cea
The Hawking-Unruh phenomenon on graphene
We find that, for a very specific shape of a monolayer graphene sample, a general relativistic-like description of a back-ground spacetime for graphene's conductivity electrons is very natural. The corresponding electronic local density of states is of finite temperature. This is a Hawking-Unruh effect that we propose to detect through an experiment with a Scanning Tunneling Microscope.
Alfredo Iorio; Gaetano Lambiase
The recursive Green's function method for graphene
We describe how to apply the recursive Green's function method to the computation of electronic transport properties of graphene sheets and nanoribbons in the linear response regime. This method allows for an amenable inclusion of several disorder mechanisms ... Keywords: Electronic transport, Graphene nanoribbons, Recursive Green's function method
Caio H. Lewenkopf, Eduardo R. Mucciolo
Vibrational analysis of graphene based nanostructures
This paper deals with the molecular mechanics simulations of graphene nanostructures and their vibration behavior for potential applications on nano-electronics and nanocomposites. The fundamental frequencies for CNTs range from 10 to 250GHz and 100 ... Keywords: Carbon nanotubes, Graphene nanosheets, Modal analysis, Molecular mechanics, Vibration
Antonio F. Ávila; Alexandre C. Eduardo; Almir S. Neto
Adsorption of small molecules on graphene
We investigate the adsorption process of small molecules on graphene through first-principles calculations and show the presence of two main charge transfer mechanisms. Which mechanism is the dominant one depends on the magnetic properties of the adsorbing ... Keywords: Adsorption, Graphene
O. Leenaerts; B. Partoens; F. M. Peeters
Graphene plasmonics for tunable terahertz metamaterials
absorption (magenta dashed line) is also present as a result of graphene absorption outside the fabricated as gate voltage Vg 2 VCNP varies from 20.3 to 22.2 V. The voltages corresponding to the unlabelled lines. Li, X. S. et al. Large-area synthesis of high-quality and uniform graphene films on copper foils
Martin, Michael C.
Graphene, neutrino mass and oscillation
A resolution of the Abraham-Minkowski dilemma is presented that other constant velocities can play the role of c in the theory of relativity. For example, in 2005 electrons of graphene were discovered to behave as if the coefficient is a Fermi velocity. Then we propose a conjecture for neutrinos to avoid the contradiction among two-component theory, negative rest mass-square and oscillation.
Z. Y. Wang
Visualizing Individual Nitrogen Dopants in Monolayer Graphene
In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy, Raman spectroscopy, x-ray spectroscopy, and first principles calculations to characterize individual nitrogen dopants in monolayer graphene grown on a copper substrate. Individual nitrogen atoms were incorporated as graphitic dopants, and a fraction of the extra electron on each nitrogen atom was delocalized into the graphene lattice. The electronic structure of nitrogen-doped graphene was strongly modified only within a few lattice spacings of the site of the nitrogen dopant. These findings show that chemical doping is a promising route to achieving high-quality graphene films with a large carrier concentration.
L Zhao; R He; K Rim; T Schiros; K Kim; H Zhou; C Gutierrez; S Chockalingam; C Arguello; et al.
Controlled doping of graphene using ultraviolet irradiation
The electronic properties of graphene are tunable via doping, making it attractive in low dimensional organic electronics. Common methods of doping graphene, however, adversely affect charge mobility and degrade device performance. We demonstrate a facile shadow mask technique of defining electrodes on graphene grown by chemical vapor deposition (CVD) thereby eliminating the use of detrimental chemicals needed in the corresponding lithographic process. Further, we report on the controlled, effective, and reversible doping of graphene via ultraviolet (UV) irradiation with minimal impact on charge mobility. The change in charge concentration saturates at {approx}2 Multiplication-Sign 10{sup 12} cm{sup -2} and the quantum yield is {approx}10{sup -5} e/photon upon initial UV exposure. This simple and controlled strategy opens the possibility of doping wafer-size CVD graphene for diverse applications.
Luo Zhengtang [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong); Pinto, Nicholas J.; Davila, Yarely [Department of Physics and Electronics, University of Puerto Rico at Humacao, Humacao, 00792 (Puerto Rico); Charlie Johnson, A. T. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)
Flexible Dielectric Films that Incorporate Multi Walled Carbon ...
The composite materials were spin coated onto one side of flexible stainless steel substrates, and graphene and graphene with PMMA films were subsequently ...
In this paper, we show that a graphene quantum disk (GQD) can be generated on monolayer graphene via structural modification using the electron beam. The electronic structure and local optical responses of the GQD, supported on monolayer graphene, were probed with electron energy-loss spectrum imaging on an aberration-corrected scanning transmission electron microscope. We observe that for small GQD, {approx}1.3 nm in diameter, the electronic structure and optical response are governed by the dominating edge states, and are distinctly different from either monolayer graphene or double-layer graphene. Highly localized plasmon modes are generated at the GQD due to the confinement from the edge of the GQD in all directions. The highly localized optical response from GQDs could find use in designing nanoscale optoelectronic and plasmonic devices based on monolayer graphene.
Zhou, Wu [Vanderbilt University; Pennycook, Stephen J [ORNL; Idrobo Tapia, Juan C [ORNL
The main objective of this program was to develop an efficient and economically viable microwave processing technique to process cobalt cemented tungsten carbide with improved properties for drill-bits for advanced drilling operations for oil, gas, geothermal and excavation industries. The program was completed in three years and successfully accomplished all the states goals in the original proposal. In three years of the program, we designed and built several laboratory scale microwave sintering systems for conducting experiments on Tungsten carbide (WC) based composites in controlled atmosphere. The processing conditions were optimized and various properties were measured. The design of the system was then modified to enable it to process large commercial parts of WC/Co and in large quantities. Two high power (3-6 kW) microwave systems of 2.45 GHz were built for multi samples runs in a batch process. Once the process was optimized for best results, the technology was successfully transferred to our industrial partner, Dennis Tool Co. We helped them to built couple of prototype microwave sintering systems for carbide tool manufacturing. It was found that the microwave processed WC/Co tools are not only cost effective but also exhibited much better overall performance than the standard tools. The results of the field tests performed by Dennis Tool Co. showed remarkable advantage and improvement in their overall performance. For example: wear test shows an increase of 20-30%, corrosion test showed much higher resistance to the acid attack, erosion test exhibited about 15% better resistance than standard sinter-HIP parts. This proves the success of microwave technology for WC/Co based drilling tools. While we have successfully transferred the technology to our industrial partner Dennis Tool Co., they have signed an agreement with Valenite, a world leading WC producer of cutting and drilling tools and wear parts, to push aggressively the new microwave technology in to the marketplace.
Dinesh Agrawal; Rustum Roy
Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy
Dirac Charge Dynamcs in Graphene Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Wednesday, 29 October 2008 00:00 Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from the University of California at San Diego, Columbia University, and the ALS has succeeded in probing the dynamical properties of the charge carriers in graphene with an accuracy never before achieved. Their results have uncovered signatures of many-body interactions in graphene and have demonstrated the potential of graphene for novel applications in optoelectronics.
Organometallic Hexahapto Functionalization of Single Layer Graphene as a Route to High Mobility Graphene Devices
Organometallic hexahapto chromium metal complexation of single layer graphene, which involves constructive rehybridization of the graphene pi-system with the vacant chromium d orbital, leads to field effect devices which retain a high degree of the mobility with enhanced on-off ratio. This hexahapto mode of bonding between metal and graphene is quite distinct from the modification in electronic structure induced by conventional covalent sigma-bond formation with creation of sp3 carbon centers in graphene lattice and this chemistry is reversible.
Sarkar, Santanu; Huang, Jhao-Wun; Wang, Fenglin; Bekyarova, Elena; Lau, Chun Ning; Haddon, Robert C
Electronic states in epitaxial graphene fabricated on silicon carbide
An analytical expression for the density of states of a graphene monolayer interacting with a silicon carbide surface (epitaxial graphene) is derived. The density of states of silicon carbide is described within the Haldane-Anderson model. It is shown that the graphene-substrate interaction results in a narrow gap of {approx}0.01-0.06 eV in the density of states of graphene. The graphene atom charge is estimated; it is shown that the charge transfer from the substrate is {approx}10{sup -3}-10{sup -2}e per graphene atom.
Davydov, S. Yu., E-mail: email@example.com [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)
Investigation of the Local Structure of Graphene Oxide
A study of the local structure of graphene oxide is presented. Graphene oxide is understood to be partially oxidized graphene. Absorption peaks corresponding to interlayer states suggest the presence of pristine graphitic nanoislands in graphene oxide. Site-projected partial density of states of carbon atoms bonded to oxygen atoms suggests that the broadening of the peak due to interlayer states in the carbon K-edge spectrum of graphene oxide is predominantly due to formation of epoxide linkages. Density functional theory suggests that multilayers of graphene oxide are linked by peroxide-like linkages.
S Saxena; T Tyson; E Negusse
Energy Band Gap Engineering of Graphene Nanoribbons
We investigate electronic transport in lithographically patterned graphene ribbon structures where the lateral confinement of charge carriers creates an energy gap near the charge neutrality point. Individual graphene layers are contacted with metal electrodes and patterned into ribbons of varying widths and different crystallographic orientations. The temperature dependent conductance measurements show larger energy gaps opening for narrower ribbons. The sizes of these energy gaps are investigated by measuring the conductance in the non-linear response regime at low temperatures. We find that the energy gap scales inversely with the ribbon width, thus demonstrating the ability to engineer the band gap of graphene nanostructures by lithographic processes.
Han, M Y
Thermal fluctuations of free standing graphene
We use non-perturbative renormalization group techniques to calculate the momentum dependence of thermal fluctuations of graphene, based on a self-consistent calculation of the momentum dependent elastic constants of a tethered membrane. We find a sharp crossover from the perturbative to the anomalous regime, in excellent agreement with Monte Carlo results for graphene, and give an accurate value for the crossover scale. Our work strongly supports the notion that graphene is well described as a tethered membrane. Ripples emerge naturally from our analysis.
F. L. Braghin; N. Hasselmann
Self-weakening in lithiated graphene electrodes.
We present a molecular dynamics study of the fracture mechanisms of lithiated graphene. Our modeli ng results reveal that lithium diffusion toward the crack tip is both energetically and kinetically favored owing to the crack-tip stress gradient. The stress-driven lithium diffusion results in lithium aggregation around the crack tip, chemically weakening the crack-tip bond and at the same time causing stress relax ation. Our simulations show that the chemical weakening effect is the dominant factor, which manifests a self-weakening mechanism in lithiated graphene. The atomistic understanding of the degradation mech anism provides guidance for the lifetime extension in the design of graphene-based electrodes.
Yang, Hui [Pennsylvania State University; Huang, Xu [Pennsylvania State University; Liang, Wentao [Pennsylvania State University; Van Duin, Adri C. T. [Pennsylvania State University, University Park, PA; Raju, Muralikrishna [ORNL; Zhang, Sulin [Pennsylvania State University
Möbius Graphene Strip as Topological Insulator
We study the electronic properties of M\\"{o}bius graphene strip with a zigzag edge. We show that such graphene strip behaves as a topological insulator with a gapped bulk and a robust metallic surface, which enjoys some features due to its nontrivial topology of the spatial configuration, such as the existence of edge states and the non-Abelian induced gauge field. We predict that the topological properties of the M\\"{o}bius graphene strip can be experimentally displayed by the destructive interference in the transmission spectrum, and the robustness of edge states under certain perturbations.
Z. L. Guo; Z. R. Gong; H. Dong; C. P. Sun
Design guide for composite-material flywheels: rotor dyamic considerations. Part I. System whirling and stability. Final report
Information to designers of flywheels is provided which will enable them to predict many aspects of the dynamic behavior of their flywheel systems when spin-tested with a quill-shaft support and driven by an air turbine. Computer programs are presented for the following dynamic analysis to obtain the results indicated: free whirling for natural frequencies versus rotational speed and the associated mode shapes; rough-type stability analysis for determining the stability limits; and forced whirling analysis for estimating the response of major components of the system to flywheel mass eccentricity and initial tilt. For the first and third kinds of analyses, two different mathematical models of the generic system are investigated. One is a seven-degree-of-freedom lumped-parameter analysis, while the other is a combined distributed- and lumped-parameter analysis. When applied to an existing flywheel system, the two models yielded numerical values for the lowest first-order forward critical speed in very close agreement with each other and with experimental results obtained in spin tests. Therefore, for the second kind of analysis, only the lumped-parameter model is implemented. Qualitative discussions as to why forced retrograde whirling is not as severe as forward whirling are also presented. The analyses are applied to the multi-material ring type flywheel systems, a constant-thickness-diskring type, and a tapered-thickness-disk type. In addition, the effects of the following flywheel design parameters on system dynamics were investigated: flywheel mass; diametral and polar mass moments of inertia; location of mass center from the lower end of the quill shaft; quill shaft length; lower turbine-bearing support stiffness; equivalent viscous damping coefficient of the external damper; flywheel dead weight; and torque applied at the turbine.
Bert, C.W.; Ramunujam, G.
Graphene with geometrically induced vorticity
At half filling, the electronic structure of graphene can be modelled by a pair of free two-dimensional Dirac fermions. We explicitly demonstrate that in the presence of a geometrically induced gauge field, an everywhere-real Kekule modulation of the hopping matrix elements can correspond to a non-real Higgs field with non-trivial vorticity. This provides a natural setting for fractionally charged vortices with localized zero modes. For fullerene-like molecules we employ the index theorem to demonstrate the existence of six low-lying states that do not depend strongly on the Kekule-induced mass gap.
Jiannis K. Pachos; Michael Stone; Kristan Temme
SMT Reflow Jig Material Analysis
The most wildly used composite material is scattering glass fiber composite ... Properties of Closed-Cell Aluminum Foams Reinforced with Fly Ash Particles.
Near-zero modes in superconducting graphene
Vortices in the simplest superconducting state of graphene contain very-low-energy excitations whose existence is connected to an index theorem that applies strictly to an approximate form of the relevant Bogoliubov–de ...
Ghaemi, Pouyan
Finite temperature Casimir effect for graphene
We adopt the Dirac model for quasiparticles in graphene and calculate the finite temperature Casimir interaction between a suspended graphene layer and a parallel conducting surface. We find that at high temperature the Casimir interaction in such system is just one half of that for two ideal conductors separated by the same distance. In this limit single graphene layer behaves exactly as a Drude metal. In particular, the contribution of the TE mode is suppressed, while one of the TM mode saturates the ideal metal value. Behaviour of the Casimir interaction for intermediate temperatures and separations accessible for an experiment is studied in some detail. We also find an interesting interplay between two fundamental constants of graphene physics: the fine structure constant and the Fermi velocity.
Ignat V. Fialkovsky; Valery N. Marachevsky; Dmitri V. Vassilevich
Charge, spin and pseudospin in graphene
Graphene, a one-atom-thick form of carbon, has emerged in the last few years as a fertile electron system, highly promising for both fundamental research and applications. In this thesis we consider several topics in ...
Abanin, Dmitry A
Graphene-Based Ambipolar RF Mixers
The combination of the unique properties of graphene with new device concepts and nanotechnology can overcome some of the main limitations of traditional electronics in terms of maximum frequency, linearity, and power ...
Electron-Photon Interactions in Graphene
Graphene's low-energy electronic excitations obey a 2+1 dimensional Dirac Hamiltonian. After extending this Hamiltonian to include interactions with a quantized electromagnetic field, we calculate the amplitude associated with the simplest, tree-level Feynman diagram: the vertex connecting a photon with two electrons. This amplitude leads to analytic expressions for the 3D angular dependence of photon emission, the photon-mediated electron-hole recombination rate, and corrections to graphene's opacity $\\pi \\alpha$ and dynamic conductivity $\\pi e^2/2 h$ for situations away from thermal equilibrium, as would occur in a graphene laser. We find that Ohmic dissipation in perfect graphene can be attributed to spontaneous emission.
Mecklenburg, Matthew; Regan, B C
Graphene nanoribbon FETs: technology exploration and CAD
Graphene nanoribbon FETs (GNRFETs) have emerged as a promising candidate for nanoelectronics applications. This paper summarizes (i) current understanding and prospects for GNRFETs as ultimately scaled, ideal ballistic transistors, (ii) physics-based ...
Kartik Mohanram; Jing Guo
Oxidation Resistance of Reactive Atoms in Graphene
We have found that reactive elements that are normally oxidized at room temperature are present as individual atoms or clusters on and in graphene. Oxygen is present in these samples but it is only detected in the thicker amorphous carbon layers present in the graphene specimens we have examined. However, we have seen no evidence that oxygen reacts with the impurity atoms and small clusters of these normally reactive elements when they are incorporated in the graphene layers. First principles calculations suggest that the oxidation resistance is due to kinetic effects such as preferential bonding of oxygen to nonincorporated atoms and H passivation. The observed oxidation resistance of reactive atoms in graphene may allow the use of these incorporated metals in catalytic applications. It also opens the possibility of designing and producing electronic, opto-electronic, and magnetic devices based on these normally reactive atoms.
Chisholm, Matthew F [ORNL; Duscher, Gerd [University of Tennessee, Knoxville (UTK); Windl, Wolfgang [Ohio State University
Graphene, Lattice QFT and Symmetries
Borrowing ideas from tight binding model, we propose a board class of Lattice QFT models that are classified by the ADE Lie algebras. In the case of su(N) series, we show that the couplings between the quantum states living at the first nearest neighbor sites of the lattice $\\mathcal{L}_{su(N)}$ are governed by the complex fundamental representations \\underline{${{\\mathbf{N}}}$} and $\\bar{{\\mathbf{N}}}$ of $su(N)$; and the second nearest neighbor interactions are described by its adjoint $\\underline{\\mathbf{N}} \\otimes \\bar{\\mathbf{N}}$. The lattice models associated with the leading su(2), su(3) and su(4) cases are explicitly studied and their fermionic field realizations are given. It is also shown that the su(2) and su(3) models describe respectively the electronic properties of the acetylene chain and the graphene. It is established as well that the energy dispersion of the first nearest neighbor couplings is completely determined by the $A_{N}$ roots $ \\mathbf{\\alpha}$ through the typical dependence $N/2+\\sum_{roots}\\cos(\\mathbf{k}.\\alpha) $ with $\\mathbf{k}$ the wave vector. Other features such as DE extension and other applications are also discussed. Keywords: Tight Binding Model, Graphene, Lattice QFT, ADE Symmetries.
Lattice quantum electrodynamics for graphene
The effects of gauge interactions in graphene have been analyzed up to now in terms of effective models of Dirac fermions. However, in several cases lattice effects play an important role and need to be taken consistently into account. In this paper we introduce and analyze a lattice gauge theory model for graphene, which describes tight binding electrons hopping on the honeycomb lattice and interacting with a three-dimensional quantum U(1) gauge field. We perform an exact Renormalization Group analysis, which leads to a renormalized expansion that is finite at all orders. The flow of the effective parameters is controlled thanks to Ward Identities and a careful analysis of the discrete lattice symmetry properties of the model. We show that the Fermi velocity increases up to the speed of light and Lorentz invariance spontaneously emerges in the infrared. The interaction produces critical exponents in the response functions; this removes the degeneracy present in the non interacting case and allow us to identify the dominant excitations. Finally we add mass terms to the Hamiltonian and derive by a variational argument the correspondent gap equations, which have an anomalous non-BCS form, due to the non trivial effects of the interaction.
Alessandro Giuliani; Vieri Mastropietro; Marcello Porta
Laser-induced quantum pumping in graphene
We investigate non-adiabatic electron pumping in graphene generated by laser irradiation with linear polarization parallel or perpendicular to the transport direction. Transport is dominated by the spatially asymmetric excitation of electrons from evanescent into propagating modes. For a laser with parallel polarization, the pumping response exhibits a subharmonic resonant enhancement which directly probes the Fermi energy; no such enhancement occurs for perpendicular polarization. The resonance mechanism relies on the chirality of charge carriers in graphene.
San-Jose, Pablo [Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, 28006 Madrid (Spain); Prada, Elsa; Kohler, Sigmund [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Schomerus, Henning [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)
Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from the University of California at San Diego, Columbia University, and the ALS has succeeded in probing the dynamical properties of the charge carriers in graphene with an accuracy never before achieved. Their results have uncovered signatures of many-body interactions in graphene and have demonstrated the potential of graphene for novel applications in optoelectronics.
Packing efficiency and accessible surface area of crumpled graphene
Graphene holds promise as an ultracapacitor due to its high specific surface area and intrinsic capacitance. To exploit both, a maximum surface area must be accessible while the two-dimensional (2D) graphene is deformed ...
Cranford, Steven Wayne
Advances in the CVD growth of graphene for electronics applications
Graphene, a monoatomic sheet of graphite, has recently received significant attention because of its potential impact in a wide variety of research areas. This thesis presents progress on improving the quality of graphene ...
Hofmann, Mario
Molecular dynamics simulation of nanoporous graphene for selective gas separation
Graphene with sub-nanometer sized pores has the potential to act as a filter for gas separation with considerable efficiency gains compared to traditional technologies. Nanoporous graphene membranes are expected to yield ...
Au, Harold (Harold S.)
Anisotropic Etching and Nanoribbon Formation in Single-Layer Graphene
We demonstrate anisotropic etching of single-layer graphene by thermally activated nickel nanoparticles. Using this technique, we obtain sub-10-nm nanoribbons and other graphene nanostructures with edges aligned along a ...
Campos, Leonardo
BN/Graphene/BN Transistors for RF Applications
In this letter, we demonstrate the first BN/graphene/BN field-effect transistor for RF applications. This device structure can preserve the high mobility and the high carrier velocity of graphene, even when it is sandwiched ...
Taychatanapat, Thiti
Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned...
NERSC Users Find That Nanodroplets of Water Can Manipulate Graphene...
Users Find That Nanodroplets of Water Can Manipulate Graphene NERSC Users Find That Nanodroplets of Water Can Manipulate Graphene April 30, 2010 Contact: Linda Vu, firstname.lastname@example.com, +1...
Substrate-Induced Band-Gap Opening in Epitaxial Graphene Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Wednesday, 26 March 2008 00:00 Prospective challengers to...
Tuning of Graphene Properties via Controlled Exposure to Electron Beams
The controlled modification of graphene properties is essential for its proposed electronic applications. Here, we describe a possibility of tuning electrical properties of graphene via electron-beam (e-beam) irradiation. We show that by controlling ...
Guanxiong Liu; D. Teweldebrhan; A. A. Balandin
Monolithically Patterned Wide–Narrow–Wide All-Graphene Devices
We investigate theoretically the performance advantages of all-graphene nanoribbon field-effect transistors (GNRFETs) whose channel and source/drain (contact) regions are patterned monolithically from a 2-D single sheet of graphene. In our simulated ...
Dincer Unluer; Frank Tseng; Avik W. Ghosh; Mircea R. Stan
Argonne CNM News: Graphene Decoupling of Organic/Inorganic Interfaces
Graphene Decoupling of OrganicInorganic Interfaces C60 monolayer STM three-dimensional rendered image of a C60 self-assembled monolayer at a domain boundary of graphene and bare...
Advanced Materials News
... Nhan Nguyen demonstrates how he performs optical measurements on a graphene-insulator-semiconductor sample structure. ...
Methods and compositions using calcium carbonate
Provided herein are compositions and methods including hydraulic cement, supplementary cementitious material, and/or self-cementing material. Methods for making the compositions and using the compositions are provided.
Constantz, Brent R. (Portola Valley, CA); Farsad, Kasra (San Jose, CA); Camire, Chris (San Jose, CA); Patterson, Joshua (Freedom, CA); Ginder-Vogel, Matthew (Los Gatos, CA); Yaccato, Karin (San Jose, CA); Stagnaro, John (Santa Clara, CA); Devenney, Martin (Mountain View, CA); Ries, Justin (Chapel Hill, NC)
Constantz, Brent R. (Portola Valley, CA); Farsad, Kasra (San Jose, CA); Camire, Chris (San Jose, CA); Chen, Irvin (Santa Clara, CA); Ginder-Vogel, Matthew (Los Gatos, CA); Fernandez, Miguel (San Jose, CA)
Constantz, Brent R. (Portola Valley, CA); Farsad, Kasra (San Jose, CA); Camire, Chris (San Jose, CA); Patterson, Joshua (Freedom, CA); Fernandez, Miguel (San Jose, CA); Yaccato, Karin (San Jose, CA); Thatcher, Ryan (Sunnyvale, CA); Stagnaro, John (Santa Clara, CA); Chen, Irvin (Santa Clara, CA); Omelon, Sidney (Willowdale, CA); Hodson, Keith (Palo Alto, CA); Clodic, Laurence (Sunnyvale, CA); Geramita, Katharine (Seattle, CA); Holland, Terence C. (Auburn Township, OH); Ries, Justin (Chapel Hill, NC)
Functional Composites: Fluorescent Carbon Nanotubes in Silica ...
About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Functional and Innovative Composites. Presentation Title, Functional ...
Cathode material for lithium batteries
A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.
Park, Sang-Ho; Amine, Khalil
Microwave Graphene Electronics Laboratoire Pierre Aigrain Ecole Normale Suprieure
et al. RMP 2011, etc...... #12;A graphene capacitor thin oxide Thick metallic gate Vdc+Vrf CQ Cgeo r
Plaçais, Bernard
NIST Researchers Hear Puzzling New Physics from Graphene ...
NIST Researchers Hear Puzzling New Physics from Graphene Quartet's Quantum Harmonies. For Immediate Release: September 8, 2010. ...
Ultrabroad-Band, Greatly Enhanced Light Absorption by Monolayer Graphene
We demonstrate greatly enhanced light absorption by monolayer graphene over a broad spectral range, from visible to near infrared, based on the attenuated total reflection. In the experiment, graphene is sandwiched between two dielectric media referred as superstrate and substrate. Based on numerical calculation and experimental results, the closer the refractive indices of the superstrate and the substrate, the higher the absorption of graphene will be. The light absorption of monolayer graphene up to 42.7% is experimentally achieved.
Zhao, Wangshi; Lu, Zhaolin
Coupling light into graphene plasmons through surface acoustic waves
We propose a scheme for coupling laser light into graphene plasmons with the help of electrically generated surface acoustic waves. The surface acoustic wave forms a diffraction grating which allows to excite the long lived phonon-like branch of the hybridized graphene plasmon-phonon dispersion with infrared laser light. Our approach avoids patterning the graphene sheet, does not rely on complicated optical near-field techniques, and allows to electrically switch the coupling between far field radiation and propagating graphene plasmons.
Schiefele, Jürgen; Sols, Fernando; Calle, Fernando; Guinea, Francisco
Energy Storage Fuel Cells Thermoelectrics Separations Materials Catalysis Sensor Materials Polymers and Composites Carbon Fiber Related Research Chemistry and Physics at Interfaces Materials Synthesis from Atoms to Systems Materials Characterization Materials Theory and Simulation Energy Frontier Research Centers Advanced Materials Home | Science & Discovery | Advanced Materials | Research Areas | Functional Materials for Energy SHARE Functional Materials for Energy The concept of functional materials for energy occupies a very prominent position in ORNL's research and more broadly the scientific research sponsored by DOE's Basic Energy Sciences. These materials facilitate the capture and transformation of energy, the storage of energy or the efficient release and utilization of stored energy. A different kind of
Highly Confined Tunable Mid-Infrared Plasmonics in Graphene Nanoresonators
Highly Confined Tunable Mid-Infrared Plasmonics in Graphene Nanoresonators Victor W. Brar,, Min observed in the 2-6 THz range, and active graphene plasmonic devices operating in that regime have been explored. However there is great interest in under- standing the properties of graphene plasmons across
Effects of ultra-violet laser irradiation on graphene
Graphene can be applied for transparent electrodes instead of indium tin oxide (ITO). For patterning of ITO, the maskless laser process was reported as a simple and fast process. Raman spectra and electrical resistances of graphene